Drain berries really well. Place them in a medium saucepan with 1/3 cup water. Heat over medium-low heat and cook, stirring occasionally, until you notice some of the berries breaking down, about 3-5 minutes.

While that’s cooking, stir together the cornstarch and 2 tablespoons water in a small bowl.

Stir in the sugar and lemon juice into the berries, then stir the cornstarch slurry to make sure it’s not clumped. Add to the berry mixture and stir constantly until the mixture thickens, about 1-3 minutes. Once it bubbles and looks thicker, it’s done. Remove from heat and transfer to a bowl or jar to cool completely, then refrigerate at least 2 hours.

Slice your butter and place it back in the refrigerator to stay cold.

Add flour and salt to the bowl of a large food processor and pulse once to combine. Add the cold butter and pulse just a few times until the butter is incorporated (mixture will be crumbly). Slowly add 2 tablespoons water while running the food processor. Let the processor run about 10 seconds, adding just a teaspoon more water at a time until the mixture comes together in a ball.

Turn the pie crust ball out onto a sheet of wax or parchment paper laid out on a clean work surface. Top with a second sheet of wax or parchment paper and roll to ¼-inch thickness. Chill 30 minutes.

Use a 3.5-inch round cookie cutter to cut circles out of the pie crust, re-rolling as needed. If the dough gets too soft, pop it back into the refrigerator to chill it for 15 minutes or so.

Spray a 12-cup cupcake pan with nonstick baking spray (the kind with flour in it) or grease and flour the cavities.

Press a round into each muffin cavity, pressing gently so you don’t poke holes in the crust. Chill the crusts for at least 30 minutes before filling.

Preheat oven to 400°F.

Grate the butter, or dice it small.

Whisk together the flour and sugar and add the butter, then use a pastry cutter to cut the butter into the dry ingredients until the mixture is crumbly.

Spoon about 1-1 ½ tablespoons of berry filling into each pie crust and top with about 1-2 tablespoons crumble. Press the crumble to compact it slightly.

Bake pies for 25-35 minutes, or until the crust is no longer opaque and the crumble looks dry. It won’t brown much. If any of the berry mixture has bubbled up to the muffin pan itself, use a butter knife to kind of clear it so it doesn’t cause the filling to harden to the pan and make the pies hard to remove.

Cool completely in the pans on the counter before removing. I find it’s easiest to remove them if they’ve been chilled. Run a butter knife gently around the edges and they should pop out.

Store in an airtight container in the refrigerator for up to 4 days or freeze for up to 3 months.