Preheat the oven to 450 degrees. Grease (4) four oz (about 118.29 ml) ramekins with butter, then dust with cocoa powder, tap out any excess cocoa.

Make sure that it is well greased and dusted or the cake could stick.

Place the chopped dark chocolate in a large mixing bowl.

In a small saucepan, melt the butter on low heat until completely melted. (*The butter should not come to a boil; it should just be thoroughly melted. The heat from the melted butter is what will melt the chocolate.)

Add the melted butter to the bowl with the chocolate pieces and let it sit for 1 minute (do not touch it!). After sitting for one minute, stir or whisk the chocolate until it is melted and smooth. (No lumps)

In a separate bowl, mix the sugar, eggs, and the egg yolks together with a hand mixer fitted with a whisk or single beater. Beat on medium speed until it is light in color, and it starts to thicken, about 1-2 minutes.

Add the egg mixture and the flour to the melted chocolate mixture. Using a spatula or small whisk, stir the mixture to combine for 1 minute.

Evenly divide the cake batter into the 4 prepared ramekins (about 3-4 ounces per ramekin).

Place the ramekins on a baking sheet and bake at 450 degrees for 8 to 9 minutes. The cakes will have puffed, and the tops will just look set but still jiggle.

Remove the cakes from the oven & let sit in the ramekin for one minute.

Place a plate onto the top of the ramekin and turn it over carefully, the ramekin will still be hot. Let sit for a few seconds then carefully remove the ramekin.

Serve immediately as desired with dusted powdered sugar, ice cream or whipped cream, or all the above.