Custard bars with summer berries-yeah, this one will see a few more forms as I play with different fillings. For now think soft and creamy custard center injected with bright berries for a punch of fruitiness that’s crusted with Christina Tosi’s famous cake mix crust.
Remember when I made Momofuku’s Ooey GooeyButter Cake Bars, but added blueberries to it to cut the sweetness? Of course the original recipe is great as is, but for my own preference, I wanted something little less sweet and a little more firm without having to freeze it. So for this recipe I started with the crust, but went with my own recipe for the filling.
To start off I bypassed the cream cheese for sour cream to lighten things. And in keeping with the goal to tone down the sweetness I dropped the sugar ratio. I changed out the pound of powdered sugar for 1 ¼ cup of sugar and threw in a little cornstarch to make up for the loss of that in powdered sugar to help set the custard. Then of course I finished custard bar recipe with lots of berries, which of course had one of my co-workers calling this a custard pie bar—she might be right, but it seems too wordy.
Summer Berry Custard Bars
Yield: Makes 1 9x13 cake
- 1 box of yellow cake mix
- 4 ounces butter, melted
- 1 egg
- 1 tablespoon lemon zest
Berry Custard Filling
- 3 large eggs
- 1 1/4 cup sugar
- 3/4 cups sour cream
- 1/2 cup flour plus 2 tablespoons
- 3 tablespoons cornstarch
- 12 oz raspberries
- 4 oz berries
- 1 tablespoon lemon zest
Heat oven to 350 degrees F and line 9x13 pan with foil and cover with bake spray.
To make crust
Place the dry cake mix, butter, 1 egg and lemon zest in a bowl and mix until well blended. Press mixture into parchment-lined 9x13 inch pan. Set aside.
To make berry custard filling
- Place egg in a bowl of stand mixer fitted with a whisk attachment. Beat eggs until well combined. Add in sugar and beat and until foamy. Add in sour cream, flour, cornstarch and mix to combine. Turn off mixer and fold in raspberries, blueberries and lemon zest.
- Pour mixture on top of crust and bake at 350 degrees for 40-55 minutes or until the edges are a light golden brown, and the center slightly jiggles when pan is tapped.
- Cool completely in pan. Turn out onto a cutting board and cut into squares.
A few notes:
- Note the crust recipe is minimally adapted by my addition of the lemon zest to balance the sweetness.
- I used frozen berries, so keep in mind the coldness of the berries will immediately thicken the mixture as it comes in contact with the cornstarch. And of course any berries will work, so use what you prefer.
- The custard bars are best served warm. To reheat, place sliced bars in the microwave for 30 seconds.
Crust (adapted from Christina Tosi's).