Dahlia Bakery
Pastry Chef Brittany Bardeleben

Blueberry filling:
fresh blueberries 700g
water 24 oz
fresh lemon juice 3 oz
cornstarch 96g
salt 1tsp
sugar 700g
second blueberries 1130g

Rinse and pick through blueberries, removing any stems and debris. Divide them into 2 bowls- first blueberries (700g), and second blueberries (1130g).

In a small bowl, whisk the cornstarch and sugar together.

Bring water, lemon juice and salt to a boil. Add first blueberries.

Cook, stirring constantly with a whisk until berries burst and release their juices.

Add cornstarch/sugar mixture and cook, whisking constantly until sauce is thick and transluscent.

Remove from heat and gently fold in second blueberries.

Pour mixture out into a casserole dish. Cover the surface with plastic wrap, and chill until cold to the touch. Meanwhile, mix the streusel topping.

Buckwheat streusel:
all-purpose flour 175g
rolled oats 175g
buckwheat flour 100g
brown sugar 340g
kosher salt 1 teaspoon
unsalted butter 340 g, cut into cubes and very slightly brought to room temperature

Put the flour, sugar, and salt in a medium-sized mixing bowl and stir to combine.

Add the softened butter in clumps, and then use your fingers to work the butter into the dry ingredients until the mixture is shaggy (you should be able to squeeze some of the mixture together with your fingers to make clumps). Scatter the crumbs over the chilled blueberry filling and bake in a 350 degree oven until streusel has browned and the filling is bubbly, approximately 40-50 minutes.