I scatter the remaining white chocolate chips over the top and press them in lightly. For a beautiful, sparkling, crunchy top, I sprinkle the entire surface with the optional turbinado sugar. It looks like a dusting of snow and gives a wonderful texture. I bake the bars for 28-32 minutes. The trick is to pull them when the top is golden and set, and a toothpick inserted into the center (avoiding a raspberry) comes out clean or with a few moist crumbs. The edges will be a deeper gold. I learned the hard way that over-baking leads to dry bars. I let them cool completely in the pan on a wire rack—this is essential for them to set properly for cutting.
Pro Tips for Best Results
For the most defined, jammy raspberry pockets and to prevent a soggy bottom, toss your frozen raspberries in that tablespoon of flour. I tested this three ways: adding them plain, thawing and draining them, and tossing frozen in flour. The flour-tossed frozen berries were the clear winner. They stayed intact, distributed evenly, and didn’t release excess liquid during baking.
To achieve the signature “melt-in-your-mouth” texture, two things are key: the brown butter and not overmixing the flour. Once you add the flour, mix just until it disappears. Overworking the flour develops gluten, which leads to tough, chewy bars instead of tender, delicate ones. I use a spatula and fold with a light hand.
For perfectly clean slices, chill the bars before cutting. Once they are completely cool at room temperature, I place the whole pan (or the lifted-out slab) in the refrigerator for at least an hour. This firms up the white chocolate and the butter in the dough, allowing you to cut sharp, beautiful squares with a hot, clean knife. Wipe the knife between each cut.
Common Mistakes to Avoid
My biggest first-time mistake was using hot brown butter. I was impatient and added the eggs right away. The heat partially cooked the eggs, resulting in a slightly scrambled, grainy texture in my batter and denser bars. Don’t do what I did! Let the butter cool until you can comfortably dip your finger in it—about 15 minutes is perfect.(See the next page below to continue…)