Heat oven to 350° and put the sliced peaches in a large bowl and sprinkle with chia seeds (or cornstarch or tapioca starch), lemon and cinnamon. Add date sugar if your peaches don’t seem sweet enough. Depending on how much juice your peaches are giving off, you might need to add a little more or less chia seed.
Let the peaches stand for about 15 minutes to thicken up and pull some of the juices from the peaches.
Put into an 8.5×11″ baking dish. If your dish is not non-stick, you can spray with a little oil.
In the same bowl, add the oats, oat flour, maple syrup, date sugar, almond butter, cinnamon, and nutmeg. Mix until it’s crumbly texture. It should be too wet or too dry.
The mixture should be crumbly. Evenly sprinkle the topping over the peaches.
Bake for 30 minutes or until the topping is starting to brown. If it doesn’t seem to be browning, turn on the broiler for a few minutes. Be sure to watch it carefully because it will start to brown quickly.