Step 1

Preheat the oven to 375°F (190°C). Adjust the oven rack to the center position. Generously butter a 9-inch pie plate.

Step 2

Nibble a blueberry or three to determine how sweet or tart it is. Toss the blueberries with the sugar, flour, lemon juice, and salt, adjusting the amount of lemon juice according to the relative sweetness or tartness of the berries. Dump the berries into the pie plate.

Step 3

In a large bowl, stir together the flour, oats, brown sugar, vanilla, and salt. Blend in the butter, using your fingertips or a pastry cutter, and mix until well combined. Crumble the topping over the berries in clumps of varying sizes.

Step 4

Bake the blueberry crumble until the berry filling is bubbling and the crisp oat topping is set and browned in places, 25 to 35 minutes. Let the crumble cool a little (but not a lot) before spooning it onto plates or into dishes and serving it warm with a scoop of ice cream plopped on top or on the side or wherever you choose.