Line the bottom of your cake form with baking paper and grease the sides. Preheat oven to 150°C (300°F).
Stir together butter and sugar until smooth. Whisk in eggs until smooth. Add flour and baking powder and stir until smooth, but not longer. Add cream and stir a few times until combined. Do not over stir.
Pour the cake batter into the cake form. Optional: tie a wet tea towel or cake strip around the cake form to ensure the cake bakes evenly across. Bake for about 60 minutes, until a toothpick comes out smooth.
Vanilla cream
Heat up the heavy cream and milk in a saucepan.
Whisk together the egg yolks, egg, vanilla, sugar, and cornstarch in a separate bowl.
When the milk first starts to bubble, remove from heat and pour half of it into the egg mixture, whisking constantly. Then pour the mixture back into the saucepan and return to the heat, whisking constantly.
Continue whisking until the vanilla cream thickens (about three minutes). Remove from heat and pour into a clean bowl. Cover with plastic wrap, placing the plastic wrap directly touching the top of the vanilla cream. Let it cool in the fridge.
Assembly
Place the cooled cake on your cake platter. Carefully cut the cake into three equal layers. Spread half of the vanilla cream and jam on the bottom layer and add the next cake layer on top. Spread the rest of the vanilla cream and jam on the next layer and add the top layer.
Mix the cream (or juice) with enough powdered sugar so that it's thick enough to stick to the cake, but still thin enough to spread. Add the almond essence (or other essence), if desired.
Spread the glaze on the top of the cake and let it drip down the sides.
While the glaze is still wet, you can decorate the top of the cake with fresh raspberries and sliced almonds, chocolate pieces, or whatever you like.
Cover the cake with plastic wrap and let the cake rest in the fridge (preferably over night).
If using whipped cream, whip the cream until fairly stiff. Use either a piping bag or spoon to cover the sides of the cake with whipped cream before serving.