The core of any truffle cake is the ganache, used either as a filling, a glaze, or folded directly into the batter. Ganache is an emulsion—a uniform mixture of two elements that naturally resist each other: water (from the cream) and fat (from the chocolate).
Agitating the mixture too vigorously incorporates air bubbles and can cause the emulsion to break, splitting the fat from the liquid and resulting in a grainy, oily texture rather than a glossy sheen.
Baking a chocolate truffle cake requires gentleness. Many premium recipes eliminate flour entirely or use only a few tablespoons, relying on whipped eggs for structure. Because these batters behave similarly to custards, high oven temperatures will cause the eggs to curdle, making the cake dry and spongy. Baking the cake at a low temperature—often in a water bath (bain-marie)—protects the delicate dairy and chocolate fats. The water bath circulates gentle, humid heat around the pan, ensuring the cake bakes uniformly. This keeps the center dense, fudgy, and intensely moist, mimicking the texture of a hand-rolled confectionery truffle.