Step 1

Preheat oven to 350° F. Grease a 9-inch square baking dish, a deep 9-inch round dish, an 11 x 7-inch dish, or a 10-inch cast iron skillet. Set aside.

Step 2

In a medium bowl, stir together the oats, flour, brown sugar, pecans, cinnamon, nutmeg and salt. Add the melted butter and stir to completely combine, making sure that there are no dry bits of flour. Set aside or chill in the refrigerator for a few minutes while you make the filling.

Step 3

In a large bowl, stir together plums, brown sugar, lemon juice, cornstarch and salt. Let sit for 5-10 minutes.

Step 4

Transfer the plums and their juices to the prepared baking dish. Distribute topping evenly over the fruit.

Step 5

Bake, uncovered, until the juices are bubbling and thickened and the top is golden brown, about 40-45 minutes. Let rest for 5-10 minutes before serving. Top with ice cream or whipped cream, if desired.