In a large bowl, combine the peaches, blueberries, lemon juice, tapioca and sugar. Set aside.

Preheat your oven to 350 degrees F. Prepare a 13x9-inch baking pan by using a pastry brush and spreading a thin layer of vegetable shortening on sides and bottom of pan.

In a mixing bowl, cream together the butter and brown sugar until smooth. Add the rolled oats, flour, salt and baking powder and stir into the creamed mixture.

Press half of the mixture into the bottom of the prepared 13x9 -inch baking pan.

Spread the blueberry and peach mixture over the crust. Crumble the remaining crust mixture over the top.

Bake for about 50-60 minutes. Or until the top is bubbly and lightly golden brown.

Let cool completely before cutting into the crumble/cobbler.