Preheat oven to 350 degrees F (175 degrees C). Grease and flour three 9 inch round cake pans.
In a large bowl, beat sugar, gelatin and butter until fluffy. Add eggs one at a time, beating well with each addition. Mix flour and baking powder, and beat alternately with the milk into the sugar mixture. Fold in 1 teaspoon vanilla and pureed strawberries. Divide equally into three 9 inch round cake pans.
Bake 25 minutes in the preheated oven, or until toothpick inserted into cake comes out clean. Cool for 10 minutes in the pans, then remove from pans and cool completely.
To make the filling: Beat whipping cream, 2 tablespoons sugar and 1/2 teaspoon vanilla on high until stiff. Fill each layer with 1/3 of the whipped cream and 3/4 cup sliced strawberries.
To make the frosting: Beat the margarine, cream cheese, confectioners' sugar, and vanilla until creamy. Spread over the sides of the cake, and pipe an edge of frosting around the top of the cake.
Spread remaining whipped cream on cake top. Top with quartered strawberries.