Preheat oven to 350 degrees
In large bowl, combine ingredients for fruit filling. Mix to combine. Pour in 9x9 or similar baking dish in uniform baking dish. Set aside.
In medium bowl, combine flour, oats, baking powder, sugar, and salt and whisk together. Cut butter into small chunks and toss in dry ingredients to coat. Work butter into dry ingredients until some pieces are very fine, and some are the size of almonds.
Make layer of topping on top of fruit mixture in baking dish.
Place dish in oven for 35-40 minutes, or until the fruit is bubbling and the top is golden brown.