A light and fluffy sponge cake with custard

👩‍🍳 Sponge Preparation: Preheat the oven to 180°C (356°F, convection). Prepare two 20 cm round cake tins — line the bottoms with parchment paper. I baked two layers separately so they would rise better, and they turned out very fluffy this way. I think you could bake the whole batter in one pan and then cut it into two layers, but I’m not sure it will rise as well. Mix the plant-based milk with vinegar and let it sit for 10 minutes — it should form a kind of vegan “buttermilk.” (Although in my case it didn’t really thicken much — it stayed mostly like milk with just a slight hint of curdling, but it didn’t affect the final texture.) Sift the flour, baking powder, and baking soda into a large bowl. In another bowl, mix the sugar with the lemon zest and rub it with your fingers to release the aroma. Add this to the dry ingredients. Pour in the “buttermilk” and oil. Gently mix until you get a smooth batter. Toss the raspberries in 2 tbsp flour, then carefully fold them into the batter — do not overmix to keep the texture light. Divide the batter between the two pans. Tap the pans lightly on the table to release air bubbles. Bake for 25–30 minutes, or until a toothpick inserted comes out clean. Let cool in the pans for 10 minutes, then transfer to a rack to cool completely. For an even softer texture, you can leave the sponge in an airtight container overnight. 🥄 Cream Preparation: Mix the starch with the sugar. Add this mixture to the milk, which should already be slightly warmed in a saucepan — this helps avoid lumps. Cook over low heat, stirring constantly, until the cream thickens. Add the butter at the end. Use a saucepan that prevents sticking, as the cream thickens and can easily cling to the sides (I use a dedicated one just for creams and sauces). For a thicker consistency, use well-chilled coconut milk (17–19% fat or higher). To make the cream more stable, you can add coconut oil or vegan butter. If lumps form, you can briefly blend the hot cream with a mixer until smooth.