Heat oven to 350°F. Grease a 9×13-inch baking dish.
Whisk pumpkin, evaporated milk, granulated sugar, 0.4 cup brown sugar, cornstarch, pumpkin spice, 1 tsp cinnamon, 0.5 tsp salt, and vanilla until smooth.
Pour the pumpkin mixture into the dish and smooth the top.
Stir oats, flour, 0.7 cup brown sugar, pecans, 0.5 tsp cinnamon, and 0.25 tsp salt in a bowl.
Drizzle in melted butter and toss until clumps form.
Scatter the crumb over the filling. Bake 45–55 minutes, until the topping is golden and the edges are set.
Cool 15–20 minutes to thicken. Serve warm with ice cream or whipped cream.
Notes
Variation: Swap pecans for walnuts or pepitas, or stir 1/2 cup mini chocolate chips into the topping. Storage: Cover and refrigerate up to 4 days; rewarm in a 325°F oven until crisp again.This recipe is an original creation inspired by classic Easy Pumpkin Pie Crisp Recipe flavors. All ingredient ratios and instructions are independently developed.