Preheat your oven to 350°F. Grease and flour a 9-inch round cake pan to prepare it for the crumble.

In a large mixing bowl, combine 2 cups of quartered strawberries with 1/2 cup granulated sugar, 1 tbsp cornstarch, and 1 tsp lemon juice. Stir gently until the strawberries are evenly coated.

Spread the prepared strawberry filling evenly across the bottom of the greased cake pan. Set aside.

In a medium mixing bowl, combine 1 cup all-purpose flour, 1/2 cup packed brown sugar, 1/2 cup rolled oats, and 1/4 tsp salt. Add 1/2 cup softened unsalted butter, mixing with a fork or your fingers until the mixture resembles coarse crumbs.

If desired, add 1/2 tsp ground cinnamon and 1/4 cup chopped walnuts or pecans to the crumble mixture for additional flavor and texture.

Evenly sprinkle the crumble mixture over the strawberry filling in the cake pan, covering the entire surface.

Place the cake pan in the preheated oven and bake for 40-50 minutes, or until the crumble topping is golden brown and the strawberry filling is bubbly.

Remove the crumble from the oven and allow it to cool for at least 15 minutes before serving. This will help the filling set and make it easier to slice.

Cut the crumble into slices and serve warm. Pair with a scoop of vanilla ice cream for a delicious treat.

Store any leftovers in an airtight container in the refrigerator for up to 3 days. Reheat in the oven before serving for best results.