Preheat the oven to 450 degrees F / 230 degrees C / gas mark 8.
Place the cubed butter and chocolate into a small bowl and microwave in 30-second increments until the chocolate is melted and the mixture is fully combined when stirred.
Using a stand mixer or handheld mixer, beat the eggs together with sugar and vanilla until foamy.
Fold the chocolate mixture into the egg mixture, then add the flour and gently mix everything until combined.
Grease the ramekins with butter and dust with cocoa powder, then divide the batter between the ramekins.
Place the ramekins on a baking tray and bake for 6 to 8 minutes, or until the outside of the cakes are firm but the centers are still soft and jiggly.
Remove from oven and let cool for 1 minute. Cover each dish with a plate and carefully invert the lava cakes. Allow them to stand for 10 seconds before removing the ramekins and serving.
To Make in the Air Fryer:
Place the cubed butter and chocolate into a small bowl and microwave in 30-second increments until the chocolate is melted and the mixture is fully combined when stirred.
Using a stand mixer or handheld mixer, beat the eggs together with sugar and vanilla until foamy.
Fold the chocolate mixture into the egg mixture, then add the flour and gently mix everything until combined.
Grease the ramekins with butter and dust with cocoa powder, then divide the batter between the ramekins.
Place the baking dishes into the air fryer basket and bake at 360 degrees F / 180 degrees C for 7 minutes. The centers should still be quite soft.
Remove from air fryer and let cool for 1 minute. Cover each dish with a plate and carefully invert the lava cakes. Allow them to stand for 10 seconds before removing the ramekins and serving.
Notes
Carefully measure the ingredients, especially the flour.
Bring all of your ingredients to room temperature before beginning this recipe.
For the best results, use four 4-ounce ramekins that measure 4 inches across.
Cooking times vary depending on the size of the ramekins, so you will need to adjust the baking time if you use a different size.
Grease the ramekins with butter and dust with cocoa powder, so the chocolate molten lava cakes release easily for serving.
If you prefer a denser cake, add 2 minutes or so to the cooking time.
Using quality dark chocolate for making lava cakes that melt perfectly, without lumps, so the dessert will turn out to be as tasty as possible.
Do not overbake. These are intentionally underbaked, so the middles stay gooey.
You can make this in the air fryer if you prefer, or check out my Crockpot Chocolate Lava Cakes recipe to learn how to make it in the slow cooker.
Serve immediately to get the very best lava cake experience.
Storage - you can store baked chocolate lava cakes in an airtight container inside the fridge for 2-3 days, however, the centers will solidify.