vegetable cooking spray
11/3 cups all-purpose flour
11/3 cups old-fashioned oats
1 cup (light or dark) brown sugar, packed
1/4 tsp. salt
2/3 cup unsalted butter, melted
6 medium-large apples, peeled, cored, and cut into 1/3-inch-thick slices
1/3 cup sugar
1 Tbsp. cornstarch
1 Tbsp. fresh lemon juice
1 (10 oz.) pkg. frozen blackberries
black raspberry ice cream (optional)
fresh blackberries for garnish (optional)