If there is no lava, Here are some reasons- Overbaked the cake. If you bake them more, the inside sets and then there’s no lava. Every minute is crucial. If you overbaked the cake, the good news is you can still eat it. It won't go to waste. Oven temperature settings are off. Every oven temperature is different. So it's a good idea to test one batch and then move forward with the rest. Over-mixed the batter.