Preheat oven to 350°F
Place pumpkin puree in a large bowl. Add melted butter and mix well.
Using an electric mixer or wire whisk, mix in brown sugar, milk, eggs, cinnamon, allspice, cloves, nutmeg and vanilla. Beat until mixtureis completely smooth.
Using vegetable spray, lightly coat the bottom of an 8″x8″ baking dish; evenly pour filling into it.
Bake about 45 to 50 minutes, or until knife inserted incenter comes out clean.
Serve with whipped cream if you wish.