1-1/2cups graham cracker crumbs
2 tablespoons light brown sugar
4 tablespoons unsalted butter, melted
1 (8-ounce) package cream cheese, softened
1/4 cup dulce de leche
3 large eggs
1 (15-ounce) can pumpkin puree
1/3 cup packed light brown sugar
1-1/4 teaspoons pumpkin pie spice
1/2 cup evaporated milk
2 teaspoons vanilla extract
1 cup sweetened whipped cream, optional