For the cocoa dough
01 -
1 1/2 cups (190 g) all-purpose flour
02 -
1/2 cup (40 g) unsweetened cocoa powder
03 -
1 teaspoon baking soda
04 -
1/4 teaspoon fine salt
05 -
1/2 cup (113 g) unsalted butter, softened
06 -
3/4 cup (150 g) granulated sugar
07 -
1/4 cup (55 g) packed light brown sugar
08 -
1 large egg, room temperature
09 -
1 teaspoon vanilla extract
10 -
3-5 drops purple gel food coloring, optional
For the filling and finish
11 -
1/2 cup (160 g) thick blueberry jam or preserves
12 -
1/4 cup (50 g) granulated sugar, for sprinkling