Preheat oven to 180 degrees C. Grease and flour three 23cm round cake tins.
In a large bowl, beat sugar, jelly crystals 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 23cm round cake tins.
Bake 25 minutes in the preheated oven, or until a skewer 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 cream, 2 tablespoons sugar and 1/2 teaspoon vanilla essence on high until stiff. Fill each layer with 1/3 of the whipped cream and 3/4 cup sliced strawberries.
To make the icing: Beat the margarine, cream cheese, icing sugar and vanilla until creamy. Spread over the sides of the cake, and pipe an edge of icing around the top of the cake.
Spread remaining whipped cream on cake top. Top with quartered strawberries.