In a large bowl, combine the strawberries, peaches, granulated sugar, lemon juice, and vanilla extract. Toss gently to coat the fruit and let it sit for about 10 minutes to allow the flavors to meld.
While the fruit is marinating, prepare the crisp topping. In another bowl, mix the rolled oats, flour, brown sugar, cinnamon, nutmeg, and a pinch of salt.
Add the cold, cubed butter to the oat mixture. Using a pastry cutter or your fingers, mix until the mixture resembles coarse crumbs.
In a greased 9x13-inch baking dish, spread the fruit mixture evenly across the bottom.
Sprinkle the oat topping evenly over the fruit layer, ensuring all the fruit is covered.
Bake in the preheated oven for 30-35 minutes or until the topping is golden brown and the fruit is bubbly.
Remove from the oven and let it cool slightly before serving.
Notes
Serve warm in individual bowls topped with a scoop of vanilla ice cream or dollop of whipped cream for an extra treat!