Serves 12 to 14

For crust
3/4 cup graham cracker crumbs (from five 4 3/4- by 2 1/4-inch crackers)
1/2 cup pecans (1 3/4 ounce), finely chopped
1/4 cup packed light brown sugar
1/4 cup granulated sugar
1/2 stick (1/4 cup) unsalted butter, melted and cooled

For filling
1 1/2 cups canned solid-pack pumpkin
3 large eggs
1/2 cup packed light brown sugar
2 tablespoons heavy cream
1 teaspoon vanilla
1 tablespoon bourbon liqueur or bourbon (optional)
1/2 cup granulated sugar
1 tablespoon cornstarch
1 1/2 teaspoons cinnamon
1/2 teaspoon freshly grated nutmeg
1/2 teaspoon ground ginger
1/2 teaspoon salt
3 (8 ounce) packages cream cheese, at room temperature

For topping
2 cups sour cream (20 ounces)
2 tablespoons granulated sugar
1 tablespoon bourbon liqueur or bourbon (optional)

Garnish: pecan halves