Brown Butter Rhubarb Bars

Brown Butter Rhubarb Bars

Rhubarb lovers and haters! These brown butter rhubarb bars are delicious enough to convert even those certain they do not like rhubarb. In these bars, blood orange juice is reduced and then caramelized with rhubarb into a shiny, beautiful, dark pink jam. Next, that jam is sandwiched between two layers of brown butter pastry, one a shortbread, the other a gooey butter cake. You now know why I earmarked this recipe some eight years ago.

Memorial day weekend is always a turning point of so many fun milestones in our lives.  We kick off the season with our anniversary being first, at the end of May, which gives way to Father’s Day, my husband’s birthday and finally, the three summer birthdays of my kids. 

cut up blood oranges

This year, things are different on so many levels.  But, that makes it all the more appropriate to celebrate holiday number 1 in the line up: our anniversary… and celebrating with food is my love language.  With both rhubarb and blood oranges finally showing up at our grocery store, I knew it was time to tackle a recipe I’ve been eyeing in The Big Sur Bakery Cookbook: A Year in the Life of a Restaurant.

We visited Big Sur and Monterey, California for our honeymoon, and then again a few years ago to celebrate our 10-year anniversary.  Sadly, the first time we were in Big Sur, we missed Big Sur Bakery and Restaurant entirely.  My brother scoped it out for us while in town for a wedding a few years later, and purchased the cookbook for me.  After cooking our way through a bunch of delicious seasonal recipes, we looked forward to the day we would get to visit.  The 2017 landslides closed a 12-mile portion of the highway south of Monterey and completely cut off access to many businesses in Big Sur.  Sadly, we missed another opportunity to check out the place for ourselves.  Third time will be a charm, right? 

In the meantime, the brown butter rhubarb bars are a perfect nod to our time together on the Big Sur coast.  They are comprised of three delicious layers: a base of flakey, brown buttery shortbread, a rhubarb and blood orange jam, and lastly, a cake-like custard layer, flecked with orange zest and vanilla beans.  Just think, these dreamy bars are cookie, cake and jam, all layered into one perfect package! 

Brown Butter Rhubarb Bars
Makes 12 bars

Rhubarb Jam:

1 cup sugar
grated zest and juice of 2 blood oranges
½ vanilla bean
4 rhubarb stalks, cut into 1/2-inch pieces

Crust:
1 cup salted butter
½ cup powdered sugar
1 ½ cups all-purpose flour

Brown Butter Filling:
3 eggs
1 ¼ cups sugar
grated zest of 2 oranges
¾ cup plus 2 tablespoons all-purpose flour
½ vanilla bean
½ cup salted butter

Make the jam:

  1. Place the sugar, blood orange zest and juice in a medium saucepan. Split the vanilla bean lengthwise with a paring knife, scraping out the pulp with the back of the knife. Put the pulp and the pod in the pan, and bring the mixture to a boil over high heat. Continue cooking until the faintest bit of caramel color starts to appear around the edge of the pot, about 4-6 minutes.
  2. Add the rhubarb and continue cooking, stirring with a wooden spoon, until the rhubarb turns into a smooth jam, 7 to 10 minutes. 
  3. Transfer the jam to a separate dish to cool while you make the crust and filling.

Make the crust:

  1. Melt the butter (1 cup) in a saucepan over medium-high heat, whisking frequently. Cook until the butter separates and the white milk solids start to brown and smell nutty, about 5 minutes, being careful not to let it burn. 
  2. Pour the hot brown butter into a dry bowl and freeze until solid, about 35 minutes. 
  3. Place the powdered sugar and flour in a bowl and mix to combine.
  4. Take out the frozen butter and break it up into small pieces with a spoon. Mix the brown butter pieces into the flour mixture, using a pastry blender until large crumbs start to form. Work the crumbs together into a crumbly dough with both hands.
  5. Line a 9 by 13-inch baking pan with two pieces of parchment paper or foil perpendicularly, with some overhanging on all four sides. This makes the bars easy to remove once they’re cool.  
  6. Place the dough into the pan, pressing it firmly with your hands into the bottom, spreading as evenly as possible. 
  7. Chill the crust in the refrigerator for 30 minutes.

–While the crust is chilling, adjust the oven rack to the middle position and preheat the oven to 375 degrees Fahrenheit. 
–Bake the crust for 15-18 minutes, until golden brown. Let it cool before assembling the bars (leave the oven on). 
–While the crust is cooling, make the brown butter filling.

Make the brown butter filling:

  1. Whisk together the eggs, sugar, orange zest and flour in a medium bowl. 
  2. Split and scrape the vanilla bean just as you did for the rhubarb jam, and put the pulp and the pod in a medium saucepan.
  3. Add the remaining 1/2 cup butter and melt over medium-high heat. Cook until the butter separates and the white milk solids start to brown and smell nutty. (Discard the vanilla bean.) 
  4. Carefully, add the warm brown butter to the egg mixture, whisking constantly until all the butter is incorporated.

Assemble the bars:

  1. Spread half of the brown butter filling over the cooled baked crust. 
  2. Remove the vanilla bean from the jam and spoon large dollops of the jam over the filling, reserving a quarter of the jam, spreading slightly.
  3. Spread the remaining brown butter filling over the rhubarb.
  4. Finish by spooning smaller dollops of the reserved jam randomly over the top. 
  5. Swirl in circles to marble the top two layers with a butter knife.
  6. Bake for 25-35 minutes, until the filling is deep golden brown. 
  7. Remove the bars from the oven and let them cool completely.
  8. Cut into 3-inch squares and enjoy!

Recipe adapted from: The Big Sur Bakery Cookbook: A Year in the Life of a Restaurant 

stacked brown butter rhubarb bars
bite out of a brown butter rhubarb bar
full pan of brown butter rhubarb bars
Print Recipe
5 from 2 votes

Brown Butter Rhubarb Bars

Homemade Rhubarb & Blood Orange Jam + Brown Butter Shortbread + Brown Butter & Vanilla Bean Gooey Cake Layer
Prep Time1 hr 15 mins
Cook Time55 mins
Time to Chill in Freezer35 mins
Total Time2 hrs 45 mins
Course: Dessert
Cuisine: American
Keyword: brown butter, brown butter rhubarb bars, rhubarb bars
Servings: 12

Ingredients

Rhubarb-Blood Orange Jam

  • 1 cup sugar
  • 2 blood oranges grated zest and juice of both oranges
  • 1/2 vanilla bean
  • 4 stalks rhubarb, cut into 1/2-inch pieces

Shortbread Crust

  • 1 cup salted butter
  • 1/2 cup powdered sugar
  • 1 1/2 cups all-purpose flour

Brown Butter Filling

  • 3 eggs
  • 1 1/4 cups sugar
  • 2 blood oranges grated zest of
  • 3/4 cup plus 2 tablespoons all-purpose flour
  • 1/2 vanilla bean
  • 1/2 salted butter

Instructions

Make the Jam:

  • Place the sugar, blood orange zest and juice in a medium saucepan. Split the vanilla bean lengthwise with a paring knife, scraping out the pulp with the back of the knife. Put the pulp and the pod in the pan, and bring the mixture to a boil over high heat. Continue cooking until the faintest bit of caramel color starts to appear around the edge of the pot, about 4-6 minutes.
  • Add the rhubarb and continue cooking, stirring with a wooden spoon, until the rhubarb turns into a smooth jam, 7 to 10 minutes. 
  • Transfer the jam to a separate dish to cool while you make the crust and filling.

Make the Crust:

  • Melt the butter (1 cup) in a saucepan over medium-high heat, whisking frequently. Cook until the butter separates and the white milk solids start to brown and smell nutty, about 5 minutes, being careful not to let it burn. 
  • Pour the hot brown butter into a dry bowl and freeze until solid, about 35 minutes. 
  • Place the powdered sugar and flour in a bowl and mix to combine.
  • Take out the frozen butter and break it up into small pieces with a spoon. Mix the brown butter pieces into the flour mixture, using a pastry blender until large crumbs start to form. Work the crumbs together into a crumbly dough with both hands.
  • Line a 9 by 13-inch baking pan with two pieces of parchment paper or foil perpendicularly, with some overhanging on all four sides. This makes the bars easy to remove once they’re cool.  
  • Place the dough into the pan, pressing it firmly with your hands into the bottom, spreading as evenly as possible. 
  • Chill the crust in the refrigerator for 30 minutes.
  • While the crust is chilling, adjust the oven rack to the middle position and preheat the oven to 375 degrees Fahrenheit. 
  • Bake the crust for 15-18 minutes, until golden brown. Let it cool before assembling the bars (leave the oven on). 
  • While the crust is cooling, make the brown butter filling.

Make the Brown Buter Filling:

  • Whisk together the eggs, sugar, orange zest and flour in a medium bowl. 
  • Split and scrape the vanilla bean just as you did for the rhubarb jam, and put the pulp and the pod in a medium saucepan.
  • Add the remaining 1/2 cup butter and melt over medium-high heat. Cook until the butter separates and the white milk solids start to brown and smell nutty. (Discard the vanilla bean.) 
  • Carefully, add the warm brown butter to the egg mixture, whisking constantly until all the butter is incorporated.

Assemble the Bars:

  • Spread half of the brown butter filling over the cooled baked crust. 
  • Remove the vanilla bean from the jam and spoon large dollops of the jam over the filling, reserving a quarter of the jam, spreading slightly.
  • Spread the remaining brown butter filling over the rhubarb.
  • Finish by spooning smaller dollops of the reserved jam randomly over the top. 
  • Swirl in circles to marble the top two layers with a butter knife.
  • Bake for 25-35 minutes, until the filling is deep golden brown. 
  • Remove the bars from the oven and let them cool completely.
  • Cut into 3-inch squares and enjoy!

Notes

Recipe adapted from: The Big Sur Bakery Cookbook: A Year in the Life of a Restaurant 


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