1/2 cup old-fashioned or quick-cooking oats
3 cinnamon graham crackers, finely crushed (about 1/2 cup)
1/3 cup packed brown sugar
2 tsp. zest and 2 Tbsp. juice from 1 lemon
4 cups thinly sliced Granny Smith apples (about 3 large)
2 cups fresh blackberries