Preheat the oven to 350 degrees F. Lightly grease an 8 or 9 inch skillet.
In a medium bowl whisk together pumpkin puree, maple syrup, vanilla extract, eggs, oat milk, pumpkin pie spice, freshly grated lemon zest and ginger and salt.
In a separate bowl combine oats, whole-wheat pastry flour, light brown sugar, pumpkin pie spice and cinnamon and salt. Melt the butter in the microwave in increments of 15 seconds, until slightly melted but not all the way. Use your hand or a fork to work it into the oat mixture until crumbly and combined.
Add about half of the mixture to the bottom of the pan. Pour the pumpkin mixture over top until completely covered. Add the rest of the oat crumble on top of the pumpkin layer and bake for approximately 30-35 minutes until the filling is set.
Let cool, top with ice cream or whipped cream and enjoy.
