Step 1

Preheat your oven to 375°F. Pit and chop the plums into a small dice.

Step 2

Combine the blueberries and plums in a bowl with 1/2 cup of brown sugar (2.8 ounces), cornstarch, and cinnamon. Mix well and pour into a 9 inch pie plate or 8 x 8 baking dish.

Step 3

Melt butter and set aside to cool slightly.

Step 4

Combine flour, baking powder, salt, oats, and remaining brown sugar in a separate bowl, whisk to combine.

Step 5

Lightly beat egg and pour into flour mixture, work it in with a fork or your fingers until the flour mixture looks like coarse crumbs.

Step 6

Spread the flour mixture evenly over the fruit filling. Add the vanilla into the melted butter and pour over the cobbler topping.

Step 7

Bake for 35 minutes, or until top is a rich golden brown and the fruit filling is bubbling.

Step 8

Allow to cool for 10 to 20 minutes before serving. Store at room temperature, covered, for up to 3 days.