Sorry that I got into this post so late. Here is my take on genoise. I always grease and flour the cake pan. Parchment paper is necessary only for easier removal. (I only bake Angel Food type cakes in a dry, ungreased pan because the need for extra volume and greasing the sides will hinder this.) Heating the eggs with the sugar in a water bath until the sugar is just dissolved will give a higher volume during beating. After beating, the egg foam should have tripled in volume, very thick and light. Don't sift the flour too soon ahead of time. This might cause the flour to compact again. I always add a little salt for better flavor. Cornstarch is very difficult to fold and has a tendency to lump. From this point on, work rapidly. I find the tall shape of the Kitchen Aid bowl not the best for folding. Using a wider, shallower bowl makes folding easier. Sprinkle about half of the flour on top of the egg foam and gently fold. Repeat this process. Fold until there are no traces of flour in the batter. As stated in previous posts, folding a small amount of batter into the warm butter will lighten the butter, making for easier folding. Pour the lightened butter back into the batter. Fold the mixture until there are no streaks of butter. Get down to the bottom of the batter as the tendency for the butter to sink. The problem with your cake is underfolding. The butter has not been completely folded into your batter, causing the heavier part of the batter to sink to the bottom during baking. Because the dire warning in recipes of "do not overfold", I think most people do not fold their batter thoroughly. If you use the correct folding techneque, don't worry about overfolding. Just fold until the flour and the butter mixtures are well incorporated into the egg foam. It is natural for the egg foam to deflate and lose some of it's volume. Bake immediately and you will have the perfect genoise. The amount of syrup to use will depend on when you plan to eat the cake and the type of filling. I use less syrup if I am serving the cake soon. I use less syrup for fillings that are on the moist side such as mousses, whipped cream, pastry cream, and fillings that have fruits; more syrup for firmer fillings such as ganache and buttercream. That is just my taste as I find most genoise cakes a bit too wet. A suggestion: one of the best book on cake baking is Flo Braker's The Simple Art of Perfect Baking. There are some wonderful recipes but the sections on basic cakes are terrific. Happy baking.