Make the Blueberry Compote by combining blueberries, granulated sugar, and water in a saucepan over medium heat. Simmer for about 10 minutes, then whisk in cornstarch slurry.

Brown the butter in a medium saucepan over medium heat until golden brown, about 5-7 minutes. Transfer to a mixing bowl to cool.

Prepare dry ingredients by whisking together flour, baking powder, salt, cornstarch, and cinnamon in a bowl.

Mix wet ingredients by beating browned butter with sugars, then add eggs and vanilla until well combined.

Combine wet and dry mixtures carefully until just combined.

Shape dough into balls, create a divot, and fill it with blueberry compote. Chill the dough for at least 2 hours.

Prepare the streusel topping by mixing brown sugar, flour, and cinnamon, then cut in chilled butter until crumbly.

Preheat oven to 350°F (175°C) and bake chilled cookies topped with streusel for 10-12 minutes.