Preheat oven to 425°. Lightly grease 8 (6-ounce) ramekins with butter or coconut oil and dust lightly with cocoa powder. Place ramekins on a baking sheet and set aside.

Fill a small saucepan with 2 inches of water topped with a stainless steel bowl that fits securely in the pan without the bottom touching the water (you want indirect heat). Place double boiler over medium heat and add the 1 cup of butter or coconut oil and chocolate chips to bowl. When water begins to simmer, reduce heat to maintain a low simmer until chocolate and butter have completely melted. Stir or whisk occasionally but do not overwork chocolate. When chocolate-butter mixture has melted, turn off heat and whisk until well combined and smooth.

While chocolate and butter melt, in the bowl of a stand mixer fitted with the whip attachment, combine eggs, egg yolks, sugar, and salt. Beat on high speed until egg mixture is pale and thick, about 6 minutes.

Slowly pour melted chocolate mixture into egg mixture and gently fold it in using a rubber spatula. Add flour and fold it in just to combine

Gently pour or scoop batter into prepared ramekins. Bake for 9 minutes or until edges and tops of cakes are crusted but centers are still moist. Transfer ramekins to a wire rack and let cakes cool for just 1 minute. Place a serving plate over top of one ramekin and invert plate, releasing cake. Repeat to plate all cakes. Serve immediately. Kitchen Note: To make the batter in advance, pour batter into greased ramekins, wrap tightly with plastic wrap, and refrigerate for 2 days or freeze up to 1 week. Move from the freezer to your fridge the night before the party, and then to the countertop 2 hours before baking. Keep the ramekins wrapped until you’re ready to bake.