I just got back from the farmer's market with Italian plums and I decided to make this wonderful plum crumble. Plums can vary in sweetness, so you may need to add in more sugar.
PIE RECIPE HELP

INGREDIENTS
Plums:
2 tablespoons dark brown sugar, packed
2 tablespoons unbleached all-purpose flour
1/2 teaspoon ground cinnamon
1/4 teaspoon ground ginger
2 tablespoons finely chopped crystallized ginger
12 to 14 Italian prune plums, halved and pitted

Topping:
1 cup unbleached all-purpose flour; spoon into dry measuring cup and level to rim
3/4 cup sugar 
1/2 teaspoon ground cinnamon
1 teaspoon baking powder
1/4 teaspoon salt

1 large egg
1 teaspoon vanilla extract
1/4 teaspoon almond extract

7 tablespoons unsalted butter, melted

INSTRUCTIONS
1. Position a rack in the center of your oven, and preheat the oven to 375 degrees F.

Plums:
1. In a medium-size bowl, mix together the brown sugar, flour, cinnamon, ginger, and crystallized ginger.

2. Add the plums, and gently stir to coat.

3. Arrange the plums skin side up in an ungreased deep 9-inch pie plate.

Topping:
1. In another medium bowl, combine the flour, sugar, cinnamon, baking powder, and salt.

2. In a small bowl, beat together the egg, vanilla and almond extracts.

2. Add the egg mixture to the flour mixture. Using your hands, mix thoroughly, squeezing and tossing and pinching handfuls of the mixture with your fingertips, to produce moist little particles.

3. Sprinkle evenly over the plums.

Bake:
1. Spoon the melted butter evenly over the topping.

2. Bake for 30 to 35 minutes, until the top is browned and the plums yield easily when pricked with toothpick. Cool on a wire cake rack.

SERVE
Serve crumble warm or at room temperature, with crème fraîche, Greek yogurt, or whipped cream.

STORAGE
Store in the refrigerator where it will keep for a few days.
To reheat leftovers, warm in preheated 300 degree F oven.