Preheat oven to 375-degrees. Melt chocolate and butter in a small saucepan, cool 10 minutes.
In the meantime, in a separate bowl, whisk eggs and sugar together.
Add vanilla and flour and whisk until flour is well mixed in.
When chocolate has cooled stir in egg mixture.
Fill 7 ounce ramekins about 3/4 of the way full with chocolate batter.
Bake for 14 minutes. You may need to add an extra few minutes of baking time depending on your elevation. The cake should be cake spongy on the top but the middle of the cake should be melty and gooey-the consistency of pudding, not too runny. Do not let it overcook. Watch these babies closely!
Once cooled, sprinkle cakes lightly with powdered sugar.
Serve with ice cream or whipped cream.