- Preheat the oven to 350ºF. Line a 9x13 baking dish with parchment paper and coat with cooking spray.
- In a large bowl, use a fork to combine 1/2 cup brown sugar, granulated sugar, and butter. Add egg yolks and vanilla and stir to combine. Add baking powder, salt and flour. Use the fork to combine for a few strokes, then use your hands to finish the mixture and incorporate all the dry ingredients. Press the dough evenly into the pan with your hands.
- Sprinkle the dough with chocolate chips.
- In the bowl of a stand mixer fitted with the whisk attachment, beat egg whites until quite frothy. Add 1 cup brown sugar and beat until meringue-like, about 5 minutes. The mixture should be glossy and thick. Spread carefully over the chocolate chips and smooth out the top.
- Bake 20-25 minutes or until beginning to dry and crack on top. Allow to cool completely before using the parchment to remove the bars from the pan, cutting, and serving.
- Firmly packed brown sugar, divided x 1 1/2 cup
- Granulated sugar x 1/2 cup
- Butter x 3/4 cup
- Eggs, separated x 2
- Pure Vanilla Extract x 1 teaspoon
- Baking powder x 1 teaspoon
- Salt x 1/2 teaspoon
- All-purpose flour x 1 3/4 cup
- Semisweet chocolate chips x 1/2 cup