I make fruit crisps pretty much all year round. In the spring, it's rhubarb custard crisp or rhubarb-strawberry crisp. Last summer was peach blueberry crisp. Then in the fall it was pear-cranberry-gingerbread crisp and apple-cranberry (I hope to perfect that recipe this fall and post it here... I didn't quite the gingerbread crisp reliable).
The other day I wanted to make peach crisp but the blueberries had already been eaten. So I used frozen raspberries instead and boy was it delicious. It's possible you could do with a bit more sugar with the fruit. When I tasted it right out of the oven it was a bit tart, but by the next day it was wonderful. That is one thing I've discovered with fruit crisps: they're always better on the second and third days. Anyways, I feel it is a public service to share this recipe for peach-raspberry crisp.
6 peaches, peeled and cut (about 2 lbs)
lemon zest (I barely had any... this was adapted from a peach-blueberry recipe so I'm thinking raspberries' tartness maybe don't need any)
2 tbsp lemon juice
2/3 cup white sugar
1 tbsp vanilla extract
1/4 cup brown rice flour (if you can tolerate gluten use all-purpose)
1 cup frozen raspberries
1 1/2 cups oats
1/4 + half of a 1/4 cup butter (or dairy-free substitute)
1/4 + half of a 1/4 cup brown sugar
(sorry for the awkward numbers - I wanted more crisp than the original recipe, which was 1 c. oats, 1/4 c. butter and 1/4 c. brown sugar)
Preheat the oven to 350F.
Combine the peaces, lemon zest, juice, white sugar, vanilla and flour in a bowl. Fold in raspberries. Let stand for 5 mins while you make the crisp.
Mix the crisp ingredients together with your hands until they're well blended. Pour the fruit into a baking dish (I use an 8x12 inch rectangular dish but I think pretty much any shape can work). Drop bits of the crisp mixture over the top as evenly as possible.
Bake for 40-45 minutes.