Rhubarb White Chocolate Blondies

This recipe was inspired by, and adapted from several recipes, including Smitten Kitchen’s Blondies, and Hummingbird High’s Rhubarb and White Chocolate Blondies.  I changed bits of both of these recipes to create my Blondies.  I have to say, though, Smitten’s Blondies are a revelation – the browned butter makes them positively divine!  They are called “infinitely adaptable” for good reason!

This recipe produces an 8×8 pan, but you could double it and make it in a 9×13.  You may or may not need to double the rhubarb jam if you make it in the larger pan (see note 1), as I made a pretty thick layer of rhubarb, due to my intense love for the stuff.

  • Author: Laura
  • Prep Time: 15 min
  • Cook Time: 20-25 mins
  • Total Time: 35-40 mins
  • Yield: 9-16 bars 1x
  • Category: Desserts and sweets
  • Method: Baking



For the Rhubarb Jam:

  • 4 c chopped rhubarb, 1” pieces (about 1 lb.)
  • 6 T Granulated Sugar

For the Blondies:

  • 1/2 c (1 stick) Butter
  • 3/4 c packed Dark Brown sugar
  • 1 egg
  • 1/2 t Vanilla Extract
  • 1 c AP Flour
  • 1/2 t Kosher Salt
  • 1 1/4 c White Chocolate chips, divided


Prepare the Rhubarb “jam”

  1. Into a 3-qt saucepan, place the cut rhubarb and the sugar.  Cook over medium heat, stirring occasionally, until sugar is melted and rhubarb begins to soften.  Cover and continue to cook for 2 minutes, then uncover and boil another 2 minutes until much of the liquid is evaporated.  You should be able to still see many, though not all of the rhubarb chunks.
  2. Set aside until Blondie is prepared.

Prepare the pan

  1. Butter (or spray) an 8×8 baking pan.  Line with parchment paper with which you will be able to “lift” the Blondie out of the pan.  Butter or spray the parchment.

Make the Blondies

  1. Preheat oven to 350F for conventional oven, or 335-340F for convection.
  2. Brown the butter:  place the butter into a small saucepan.  Heat over Medium-low/Medium until butter melts.  Continue to heat for several minutes.  The butter will begin to spatter a bit, but keep heating until eventually, it stop spattering and will begin to foam.  Be patient, this takes several minutes.  Watch closely as the butter begins to foam up a bit.  It’s ok to stir if you feel the need.  You will eventually see a bit of tan or “brown” coming to the surface of the foam. The butter will begin to smell a bit “nutty”.  You can let it go 30 seconds or so at Medium-Low heat, but be sure to remove it before it burns.
  3. In a mixing bowl, place the brown sugar.  Pour the browned butter over the sugar and stir until incorporated.  The mixture should be only slightly warm to the touch at this point.  Crack the cold egg over the mixture, stir until smooth.  Add the vanilla.  Stir vigorously until mixture is nice and smooth.
  4. Add the flour and salt and stir to incorporate, but do not over-mix.  The batter will be quite thick.
  5. Fold in 1 cup of the white chocolate chips. Spread the batter into the prepared baking pan and level the top as much as you can with a knife or offset spatula.
  6. Using a slotted spoon, spoon the rhubarb jam over the Blondie batter.  It’s ok to not use all of the liquid.  (I probably left 3 T of liquid in the pan.)
  7. Sprinkle remaining 1/4 cup (or more if you like) chocolate chips over the rhubarb.
  8. Bake 20-25 minutes.  Check half-way through.  If the white chips are browning more than you like, place a foil “tent” over the pan.  It’s difficult to tell when they are done, but a little undertaking is better than overbaking.  I took mine out of the oven at 22 minutes and they were perfect!


  1. You could use half the amount of rhubarb if you want – 2 cups 1” rhubarb chunks with 3 T sugar, in order to produce a thinner layer, if you like.  Everything else in the recipe could stay the same.
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