Preheat the oven to 375 degree F.

Peel off the skin of the peaches with the small sharp knife and cutting board.

Cut the peaches into slices with the knife. First make a cut into the peach from top to bottom, then do the same cut about a quarter inch to the right. Then scoop the knife under the peach flesh to cut it away from the peach. Peach slices can be put on the cutting board or directly into the pitcher. Repeat the process until all of the peach is sliced up. Discard the peels and the pits.

Place the peaches in a large baking dish, either a 9x13 rectangular one or a large oval one of similar size. Spread them into an even layer.

Wash and dry the blueberries, then spread them out in the dish on top of the peaches.

Combine the remaining ingredients for the topping into a large bowl, measuring the right amount with measuring cups and spoons, and mix with a wooden spoon until well combined.

Pour the topping into the dish and spread evenly over the fruit with the wooden spoon.

Place the dish in the oven and cook for 40 minutes, until top is golden brown and filling is bubbling.

Serve by itself, with ice cream, or whipped cream on top.