Butter, for greasing the pie dish
1/4 cup quick cooking tapioca pearls, such as Minute Tapioca
1 pound frozen blueberries, thawed and drained, or 1 1/2 cups fresh blueberries
1 pound frozen peaches, thawed, or 3 large fresh peaches, pitted and thinly sliced
1/2 cup brown sugar
2 tablespoons fresh lemon juice
2 teaspoons pure vanilla extract
1 1/2 teaspoons ground cinnamon
Zest of 1 large lemon
One 9-inch unroll-and-bake refrigerated pie crust
1 egg white, lightly beaten
1/2 cup slivered almonds
1/2 cup (1 stick) butter, cut into 1/2-inch pieces, chilled
1/2 cup quick cook oats
1/2 cup almond flour
1/2 cup brown sugar