01 -
In a skillet over medium heat, melt the butter, stirring as it foams, turns amber, and brown solids form at the bottom. Once golden and fragrant, remove from heat. Transfer to a bowl and cool for 20 minutes.
02 -
In a bowl, sift together flour, cornstarch, baking soda, baking powder, and salt. Set aside.
03 -
In a large bowl, combine the cooled brown butter, granulated sugar, and brown sugar. Stir until smooth, then mix in eggs and vanilla.
04 -
Gradually fold dry ingredients into the wet mixture until just combined.
05 -
Wrap dough in plastic wrap and refrigerate for at least 1 hour.
06 -
While dough chills, combine blueberries, sugar, and lemon juice in a saucepan. Cook on medium, stirring, until thickened, about 30 minutes. Set aside.
07 -
Preheat oven to 350°F (175°C). Line a baking sheet with parchment. Scoop 3 oz balls of dough, placing them 2 inches apart. Bake for 12 minutes, until edges are golden and centers soft.
08 -
Let the cookies rest just for a minute or two then gently press the center of each with a small glass or shot glass to create a well for the blueberry jam. Spoon the prepared blueberry jam into each well, filling to the top. Serve and enjoy this irresistibly delicious treat!