Mix peanut butter with powder sugar till it makes a crumbly mixture ,set aside. In a sauce pan mix milk, water and cornstarch, cook on med to high heat stirring constantly till it thickens as a pudding consistency, turn off heat add butter and vanilla. let cool. Spread 1/2 p butter mixture in bottom of precooked cooled pie shell, add pudding, next cover with . Sprinkle remaining p butter mixture on top of meringue bake in 325 degree oven till meringue is light brown.