In a stand mixer with the whisk attachment on high-speed whisk together the eggs, sugar, salt, and vanilla extra until it turns white and is light and fluffy, which takes about 3-4 minutes. Set aside.
Bring a medium-size pot a third filled with water to a low simmer over low-medium heat. Add the butter and chocolate in a metal bowl and place them onto the pot once it is lightly simmering. Constantly stir using a rubber spatula until completely melted and smooth.
Pour about a ½ cup of the melted chocolate into the whisked egg and sugar mixture and fold together using a rubber spatula for 20 to 30 seconds to temper the eggs. Pour in the remaining chocolate and fold until completely mixed in.
Next, fold in the flour using a rubber spatula until mixed in.
At this stage, you can add them to buttered and floured ramekins and bake or spread them out on a 13x9 casserole dish and place it in the refrigerator until completely cool, which takes about 30-45 minutes.
Butter and flour 6 8-ounce ramekins or 6 3 inches in diameter by 4” tall baking cylinders and place on a cookie sheet tray lined with parchment paper.
Scoop out the batter and evenly distribute it across the ramekins or cylinders. See note on doubling batter for bigger taller lava cakes.
Bake in the oven at 450° for 9 minutes on the dot.
If using a ramekin, invert on a plate for 10 seconds and remove or pull the cylinder up and use a spatula to transfer it to a plate.
Garnish with optional whipped cream, chocolate sauce, strawberries, ice cream, a dusting of cocoa powder, or a dusting of powdered sugar, and serve.
Notes
Make-Ahead: The batter can stay covered in the refrigerator for up to 2 days before being transferred to the buttered and floured ramekin and baked.How to Store: Cover and keep in the refrigerator for up to 3 days. You can freeze this, but the soft inside will harden once reheated. Cover and freeze for up to 3 months. Thaw in the refrigerator before reheating.How to Reheat: This will harden quite a bit in the center when reheating. Place on a cookie sheet tray lined with parchment paper and bake it in the oven at 350° for 3-4 minutes.To make extra-large lava cakes, simply double the amount of batter into the cylinders or ramekins, which would take the number of servings from 6 to 3. Bake for the same amount of time. You can add 1 ounce of Baileys Irish Cream or Kahlua when folding in with the chocolate to enhance or change the flavor.Feel free to use semi-sweet chocolate if dark or bittersweet is not available.It is best to use good baking chocolate for melting purposes as opposed to chocolate chips.When the batter is cool, it will resemble a firm ganache.You will know the water in the pot for the double boiler is lightly simmering when you see little bubbles collect on the bottom of the pot.