Amish Vanilla Pie

1/2 c. firmly packed brown sugar
1 tbsp. flour
1/4 c. dark corn syrup
1 1/2 tsp. vanilla
1 egg, beaten
1 c. water
1 c. flour
1/2 c. firmly packed brown sugar
1/2 tsp. cream of tartar
1/2 tsp. baking soda
1/8 tsp. salt
1/4 c. butter
1 unbaked 9" pie shell

Combine first 5 ingredients in 2 quart saucepan. Slowly stir in water. Cook over medium heat until mixture comes to a boil, stirring constantly. Let cool. Combine rest of ingredients (except pie shell) and mix until crumbly. Pour cooled mixture into pie shell and top with crumbs. Bake at 350 degrees for 40 minutes or until golden brown.