I wouldn't add whipping cream to lighten up the pastry cream. The filling supports the top layer. The weight of the top layer of the cake will cause the filling to ooze out of cake. This is my favourite recipe for Boston Cream Pie. The filling is delicious. Boston Cream Pie ================ 1/3 cup butter 1 cup sugar 1 egg 1-1/2 cups sifted all-purpose flour 2-1/2 teaspoons baking powder 1/4 teaspoon salt 2/3 cup milk 1/2 teaspoon vanilla Cream the butter and sugar until light and fluffly. Add the egg and beat until creamy. Sift the flour, baking powder, and salt together. Add alternately with the combined milk and vanilla. Turn the batter into a greased and floured 9-inch round layer cake pan. Bake in a 350� oven for about 30 minutes, or until the cake springs back when lightly touched in the center. Cool on a rack for 5 minutes, then turn out and cool completely; Place the cake on a serving plate and split horizontally into two layers with a serrated knife. Carefully remove the top layer. Fill with the chilled Cream Filling. Replace the top half and pour the warm Chocolate Icing over the top, spreading only to the edges. Chill. (When allowed to stand for several hours, the filling seeps into the cake, making the cake and filling seem almost as one.) Cream Filling 1/2 cup sugar 3 egg yolks 3 tablespoons flour 1 tablespoon butter 1/4 teaspoon salt 1/2 teaspoon vanilla 1 1/2 cups milk Combine the sugar, flour, and salt in a saucepan. Gradually stir in the milk. Cook over low heat, stirring until the mixture comes to a boil. Boil, stirring for 1 minute. Beat the egg yolks slightly. Gradually stir in about half the thickened sauce. Return to the heat and cook. stirring 2 or 3 minutes longer to take away the flour taste. Remove from the heat and blend in the butter. Strain into a bowl. Cool for a few minutes, then blend in the vanilla. Cover and cool, then chill. Chocolate Icing 2 squares of chocolate 1 cup sifted icing sugar 2 tablespoons butter 1 tablespoons hot water 1 teaspoon vanilla Melt the chocolate and butter the microwave on medium low power. Stir until smooth, and blend in the icing sugar and hot water. Stir until smooth and slightly thickened (do not beat). Stir in the vanilla. Use immediately.

"OK, wasn't sure. It would be whatever comes with it or as sold as refills. Does that effect the stability of the cream" Read this: "--------The N2O gas is extremely soluble in fatty compounds. In aerosol whipped cream, it is dissolved in the fatty cream until it leaves the can, when it becomes gaseous and thus creates foam. Used in this way, it produces whipped cream four times the volume of the liquid, whereas whipping air into cream only produces twice the volume. If air were used as a propellant, oxygen would accelerate rancidification of the butterfat; nitrous oxide inhibits such degradation. Carbon dioxide cannot be used for whipped cream because it is acidic in water, which would curdle the cream and give it a seltzer-like 'sparkling' sensation. However, the whipped cream produced with nitrous oxide is unstable and will return to a more liquid state within half an hour to one hour. Thus, the method is not suitable for decorating food that will not be immediately served.--------" dcarch

I actually have a file on this, originally dated 2004, and updated whenever I find out more info. Maybe this will help you...the info is from a variety of sources--apologies if a source is another poster and I neglected to give that info! Smiles, Sooz Recipe for stabilizing whipped cream from the Wilton year book 1tsp Unflavored gelatin 4tsp Cold water 1cup Heavy whipping cream 1/2 tsp vanilla 1/4 C powdered sugar Combine gelatin and cold water in a saucepan. Let stand until thick. Place over low heat, stirring constantly, just until gelatin dissolves. Remove from heat and cool to lukewarm. DO NOT LET IT SET. Whip cream, sugar, and vanilla until slightly thickened. While beating slowly, gradually add the gelatin to whipped cream mixture. Whip at high speed until stiff. Remember: Cakes iced with whipped cream must be stored in the refrigerator. ** ** TIP: To stabilize Whipped Cream Frosting, in cup, sprinkle 1 teaspoon unflavored gelatin over 2 tablespoons cold water. Place cup over simmering water until gelatin is dissolved, stirring occasionally; cool to lukewarm. Gradually beat into cream before adding sugar. ***** from woodny (woody?) on Sat, Jul 20, 02 at 23:43 I do catering and these are the teqniques that have worked for me. You can purchase Whipped cream frosting in vanilla and chocolate flavors at most cake supply stores. The ones that specialize in cake decorating/supplies not just someone who carries supplies(like Michaels or Joanns). They usually come in quart, 1/2 gallon and gallon sizes. These are the whipped cream frosting that are used on most bakery cakes. If you are going to eat the cake with in 1-2 hours after frosting it the powdered sugar will be enough to keep it stable. *** Here are two ways that I stabalize whipping cream: 1. There is a product you can buy in the grocery store called WHIP IT. (It is NOT the same thing as dream whip. Do NOT use dream whip as a substitute.) You can usually find it in the foreign/ethnic food section. It is made by OETKER. It works great. It comes in packets about the size of Kool-aid packets. There are two that are stuck together side by side. The package is light blue with dark blue lettering. It says "Oetker, WHIP IT, stabalizer for whipping cream." (This is a long explaination but everytime I send some one to find it they can't so I have learned to give detailed descriptions.) Anyway . . . I will frost a wedding cake with it and it will last 2 or three days. This is MY preferred method. It is the easiest and cheapest way for me.

I agree........and now there is the Cool Whip Free that is supposed to be sugar free, but whether it is sugar replacement free might be another thing. I've not tried it yet so I don't know. I do have a lot of recipes that call for Cool Whip and lots of times I will use whipped cream depending on the occasion. If I want something to taste especially rich, I will use a little whipped cream instead of a lot of Cool Whip.