Preheat oven to 425 degrees F. Generously butter and dust four 6 oz ramekins with cocoa powder and set aside. Basic glass ramekins work very well for baking this dessert.
In a medium microwave-safe bowl, melt the chocolate and butter in 20 second increments, stirring after each 20 seconds. Continue until mixture is smooth and cool slightly. Set aside.
Whisk the flour, sugar and salt together in a small bowl.
Beat the eggs and egg yolks together with a hand mixer until they are fluffy and light yellow.
Add the chocolate mixture, dry ingredients, and vanilla to the egg mixture and mix with a spatula just until combined.
Spoon batter into the prepared ramekins evenly.
Place the ramekins onto a baking sheet and bake for 12-14 minutes or until the edges are pulling away and the center is not raw but soft to touch. Tops should look barely set.
Cool for 1-2 minutes and go around the edges with a knife. Invert ramekins onto a serving plate and turn over upside down. Use an oven mitt because the ramekins are very hot! The cakes should release easily onto the plate.
May dust with powdered sugar. Serve with desired toppings such as ice cream, chocolate sauce, whipped cream and raspberries or strawberries and enjoy!
Serve immediately. Cake is best served right away while still warm and gooey.
Notes: *Use high quality chocolate like Baker's or Ghrirardelli. You will need 1 1/2 of the chocolate packages because they are sold in 4 oz size. Chocolate chips will not give you the same liquid center as bar chocolate. *The batter for this recipe can be made ahead, placed in the ramekins, covered and refrigerated for up to two days. Bring the cake batter to room temperature before baking. *Ramekins with unbaked batter can be frozen for up to two weeks. Thaw for about an hour then bake 5 minutes longer. *Cakes are best when warm, fresh and gooey.