Preheat oven to 375 degrees.

Press the pie crust into a deep dish pie plate. This recipe makes a lot of filling, so a very large, deep pie plate is best.

Blend the egg, pumpkin and condensed milk in a large bowl. In a small bowl, combine spices and add to pumpkin. Pour mixture into the unbaked pie shell.

Combine the brown sugar, flour, chopped pecans, butter and cinnamon with a fork until crumbly. Carefully sprinkle crumb mixture on top of pumpkin.

Bake for 50 to 55 minutes or until a knife inserted in near the center comes out clean.

Cool before serving. Serve with whipped topping.