Preheat oven to 425°F. Generously spray 4 small custard cups with nonstick baking spray then place on a baking sheet.
Using a double boiler, add coconut oil and baking chocolate and boil until melted string occasionally.
Remove from the double boiler, and add to a stand mixer with the paddle attachment. Stir in sugar until smooth.
Add eggs and egg yolks then beat for 1 minute.
Add flour then stir until just combined.
Evenly spoon batter into prepared cups. Bake for 10 minutes, or until the sides are firm but the centers are still soft (but not jiggly).
Let cool for 2 minutes, then gently loosen cakes from custard cups by sliding a knife around the edges of each cake; then invert cakes onto serving plates.
Dust with powdered sugar (optional) and serve immediately (because the cakes will continue to cook in the center).
