12. Bake for 35 minutes then test with a toothpick it to see if done. If not done, continue baking for 5 minute intervals until the toothpick comes out clean. Then increase the oven temperature to 170 C or 340 F for 3 minutes to make the top golden
13. Remove from oven and place on counter to cool down. When cake is at room temperature, loosen the spring and remove the rim. Gently peel off the side parchment. With the use of a wire rack or second plate, flip the cake and remove the bottom parchment liner, then again flip the cake back upright
16. Add the whipping cream and mix at low speed for about 30 seconds, then increase the speed to high and whip until stiff peaks form. Cover the bowl with cling wrap and place in the refrigerator until ready to use
17. When the cake is completely cooled, remove from fridge and cut into half (top and bottom). Carefully remove the top layer – use support when removing the top layer so that it does not crack. Set aside
20. Carefully place the top half of the lemon sponge cake on top of the frosting and then repeat the piping out of frosting to the top of the cake. Repeat until there is frosting that reaches the top rim of the cake pan
26. OPTIONAL: What you use to decorate the top is up to you. Fresh fruit such as thinly-sliced strawberries are both attractive and complement the lemon freshness and mascarpone whipped cream frosting. Alternatively, use lemon peel ribbons, or make swirls with some of the frosting.
When you cut the cake or want to separate the top and bottom, be very careful as this cake is more fragile than a gluten cake. Slide a thick cardboard or thin flat sheet, or very wide spatula, for support. Should the top cake portion crack in spite of your best effort, place it back on top of the middle section frosting, and as Julia Child would say in her videos, “It’s just you and me, and no one else saw it (paraphrased) so don’t worry.” After arranging the top layer just spread a very thick layer of frosting on top. When the cake has rested and you have decorated it, no one will know about the little mishap. They will be amazed at how great and lemony this grain-free and sugar-free cake tastes. As you make this a couple of times, your technique will improve and soon you will master how to make the cake because this is a very easy recipe to do.
The mascarpone frosting I used is just one type of frosting. You could substitute the Swiss Buttercream Frosting (as used in the Chocolate Swiss Roll recipe) instead.
Also, if you are serving for a more casual event such as family dinner, or coffee with friends, top the cake with confectionery sweetener. Take whatever sweetener you prefer and grind to a very fine consistency. Use a small fine sieve to dust the top.