Preheat the oven to 425 degrees F and prepare the pan. Use a paper towel to spread 1 tablespoon of butter inside 8 cups of a muffin pan.

Melt the butter and chocolate. In a large microwave-safe bowl, melt the 1/2 cup of butter and chocolate chips. Cook in the microwave for 30 seconds at a time, stirring in between until liquified (about 60 seconds total).

Prepare the eggs. Crack 1 egg into a medium bowl and remove any shell. Repeat with the second egg. For the 3 egg yolks, separate the eggs easily by cracking 1 egg at a time over the sink. Pour the egg into a clean palm and allow the whites to slip through your fingers. Place the yolks in the mixing bowl. Stir to combine.

Mix the batter. Whisk tog ether the sugar and melted chocolate, making sure there are no lumps. Add the egg mixture, vanilla and flour. To add the flour correctly, use a second measuring cup, flatten off the top and pour the flour into the mixing bowl. Stir gently until completely mixed, scraping down the sides of the bowl with a silicone spatula or wooden mixing spoon as needed.

Bake the cakes. Use an ice cream scoop to spoon the batter evenly into the 8 buttered muffin cups. Bake for 8 minutes (extra gooey inside) to 10 minutes (slightly runny inside).

Serve the cakes. Allow the cakes to cool for 3 to 5 minutes. Place a cutting board on top of the muffin pan, then flip the pan so the cakes gently fall. Carefully serve the cakes on small plates and top with ice cream or whipped cream.