01 -
Set your oven rack in the middle and warm it to 375°F (190°C). This temp works great to bubble up the fruit while making the topping nice and crispy.
02 -
Grab a bowl and throw in the blueberries, peach chunks, brown sugar, lemon juice, and cornstarch. Stir everything gently until the fruit gets coated with the sugar mix. The cornstarch will thicken the juicy stuff while the lemon keeps the peaches looking fresh. Dump this mix into an 8x8-inch baking dish.
03 -
Toss the chopped pecans, cold butter chunks, cinnamon, brown sugar, flour, and salt into your food processor. Give it a couple quick pulses to mix things up a bit. Add the oats and pulse 2-3 more times. You want chunky bits with visible butter pieces - don't blend it too much or you'll end up with mush instead of crumbles.
04 -
Scatter your nutty oat mix all over the fruit. Cover everything but don't pat it down - keeping it fluffy helps it get crunchy and brown better.
05 -
Pop it in your hot oven for about 25-35 minutes until the top turns golden and you see fruit juice bubbling around the edges. If the top starts getting too brown (usually after 25 minutes), just lay some foil loosely on top. Cooking time might change depending on how juicy your fruit is and how your oven works.
06 -
Take it out and let it rest for at least 5 minutes on a cooling rack. This lets the filling firm up a bit so it's easier to serve. Want the full experience? Add a scoop of vanilla ice cream on top for that awesome hot-cold combo.