Preheat the oven to 375℉. Have a 9x13-inch baking pan ready.
To prepare the topping: In a medium mixing bowl, stir together the 2 cups old-fashioned oats, 1 cup flour, ⅔ cup brown sugar, 1 teaspoon ground ginger, and ½ teaspoon fine sea salt. Mix in the melted 8 tablespoons unsalted butter and stir until the mixture is moistened and well combined. Place the bowl in the fridge to chill while you make the filling and the oven heats.
To prepare the filling: In a large bowl, mix together the 9 cups fruit, ⅔ cup brown sugar, 4 tablespoons arrowroot starch, 2 teaspoons vanilla extract, and 1 teaspoon ground cinnamon.
Spread the filling in an even layer in the baking pan. Remove the topping from the fridge (break it up a bit if necessary) and distribute it evenly over the top of the filling.
Place in the oven and bake for 40-45 minutes, until the filling is bubbling around the edges and the top is lightly golden. Remove from the oven and let rest for at least 15 minutes before serving.
Notes
CN's Best Crisp Tips:
Chill the topping. I always place my bowl of topping in the fridge to chill while I make the filling. This lets the butter firm up slightly, making for a crisper topping later. If you find that the topping is too firm when you take it out of the fridge, break it up with your hands before scattering it over the filling.
Enjoy at any temperature. Crisp tastes amazing warm, at room temperature, or even straight out of the fridge.
Let it rest. After removing the crisp from the oven, let it sit for at least 15 minutes so that the filling sets up a bit.
Sweeten to taste. Some fruit will be on the sweeter side, depending on how ripe it is or what type it is. You may want to add more or less sugar after tasting the fruit (I always recommend doing this before you start to make the crisp so that you have an idea of how sweet or not the fruit you're using is).
Make it smaller. This makes a large amount of crisp, great for larger gatherings, but if you want to whittle it down a bit, simply halve the recipe.
To serve: Vanilla ice cream is my favorite accompaniment to crisp, and whipped cream or a drizzle of salted caramel sauce is also lovely. Or enjoy crisp at breakfast with regular or Greek yogurt.