Combine the pumpkin, cream, eggs, sugar, 1/4 cup brown sugar, bourbon, if using, ginger, nutmeg, 1/4 teaspoon cinnamon, 1/8 teaspoon salt in a large bowl. Whisk until evenly combined and pour into the prepared baking dish.
Cut the butter into small pieces and add to a medium bowl. Stir in the pecans, flour, and the remaining 1/4 cup brown sugar, 1/4 teaspoon cinnamon, and 1/8 teaspoon salt and mix until it holds together somewhat but still crumbles. Scatter the topping over the pumpkin mixture and bake until the edges are puffed and the filling is set in the center, about 45 minutes to 1 hour. Remove to a rack to cool to room temperature. Serve with the Bourbon Whipped Cream and/or ice cream.
Bourbon Whipped Cream: