Step 1

Heat the oven to 400°F and place a baking sheet on the middle shelf. Have ready a 9-inch pie plate.

Step 2

To make the topping, stir all of the ingredients in a small bowl with a fork, until the mixture holds together when squeezed, and place in the refrigerator.

Step 3

To make the egg wash, whisk the egg and salt together in a small bowl.

Step 4

To make the crust, whisk the dry ingredients in a large mixing bowl. Heat the butter and milk together in either a 2-cup glass measuring cup or a glass bowl in a microwave on high, in 3 thirty second bursts, stirring in between each, until the butter is melted and the milks is steaming hot - the mixture doesn't need to boil. Pour the hot liquid over the flour mixture and stir with a fork until the mixture holds together when squeezed and there are no loose bits of flour left in the bowl. Evenly press the dough onto the bottom and up the sides of the pie plate using your fingers. Flute the edges and brush them with the egg wash.

Step 5

To prepare the berries, whisk the sugar, cornstarch, ginger and salt in the same bowl in which you prepared the crust. No need to clean it. Stir in the berries and lemon juice with a flexible spatula. Transfer the berries to the crust, pressing them down gently and top with the crumble, using your fingers to pinch it into small, round(ish) crumbs, and pressing that down gently, as well.

Step 6

Place the pie on the preheated baking sheet and bake for 15 minutes. Reduce the heat to 375°F and bake for 45 to 55 minutes more, rotating the pie and tenting it with foil at the halfway mark, until the berries are vigorously bubbling between the crumbs in the center of the pie.

Step 7

Bring the pie to room temperature before serving in order to ensure the filing is set, about 4 hours. Keep the pie wrapped on the counter for up to 3 days.