Step 1

In a small mixing bowl, combine the flour, oats, brown sugar, butter, and cinnamon. Use a fork to mix just until combined. Refrigerate while you prepare the filling.

Step 2

In a separate large mixing bowl, combine the pumpkin puree, eggs, evaporated milk, sugars, and spices. Mix by hand or using a hand mixer until completely combined. Pour the filling into a greased 8x11 inch baking pan.

Step 3

Remove the topping from the refrigerator and crumble it evenly over the filling in the pan. Bake at 375°F for 45-50 minutes, until the topping is dark golden brown and crispy.

Step 4

Remove from oven and cool slightly before serving. Top with ice cream or whipped cream as desired.