Molten lava cakes are nearly always baked in ramekin dishes and have four main ingredients: butter, eggs, sugar, and chocolate. Unlike most cakes, this recipe does not use flour. The butter and chocolate are melted together, while the eggs are either whisked with the sugar to form a thick paste, producing a denser finished product, or are separated so the egg whites can be whipped into an egg foam to provide more lift (and thus a lighter cake) when the mixture is baked.