Batter: Grease Tiara pan (no need to flour) Blend together cake mix, eggs, butter and water on low, until moistened. Mix at medium speed for 4 minutes. Place 2 2/3 cps batter in the pan (you'll have batter left over to make 8 cupcakes) Bake at 375 for 18-21 minutes. Cool in the pan on a rack for 5-10 minutes, then invert cake onto wire rack and allow to cool completely. Mousse: Fold the butter flavor gently into the whipped topping until the color is uniform. Spread evenly in the cooled cake. Refrigerate for 30 minutes. Spoon the pie filling over the mousse, leaving an edge of mousse showing. Chill 2 more hours.