Heat the oven to 350 degrees F and arrange a rack in the middle. Coat an 8 by 8-inch baking dish with butter and set aside.
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:
Add the heavy cream to a medium bowl. Beat the cream with a hand-held mixer until thick and frothy. Add the sugar and bourbon and beat until medium peaks form.