Preheat the oven to 350°F (175°C).

Place the pre-made pizza crust on a pizza stone or baking sheet.

In a mixing bowl, combine melted butter, brown sugar, granulated sugar, ground cinnamon, and 1/2 teaspoon vanilla extract. Mix until well combined.

Stir in the flour and rolled oats until a crumbly mixture forms. If using, fold in the chopped nuts.

Spread the crumb mixture evenly over the pizza crust, pressing down lightly to adhere.

Bake in the preheated oven for 15-20 minutes, or until the crumb topping is golden brown.

While the pizza is baking, prepare the cream cheese topping by beating the softened cream cheese, powdered sugar, and 1 teaspoon vanilla extract together until smooth.

Once the pizza is done baking, remove it from the oven and let it cool slightly.

Spread the cream cheese mixture over the warm crumb topping.

Slice the dessert pizza and serve warm, topped with whipped cream if desired.