Preheat your oven to 425°F (220°C). This step is crucial for achieving that perfect lava effect. While your oven is heating, you can prepare your ramekins.

Generously grease four ramekins with butter and dust them with flour to prevent the cakes from sticking later. Be sure to tap out any excess flour. Setting them aside, let’s get to melting the chocolate.

In a microwave-safe bowl, combine the chopped bittersweet chocolate and the butter. Microwave in 30-second intervals, stirring in between until it’s completely melted and smooth. If you’re worried about burning it, you can use a double boiler.

In a separate bowl, whisk together the two whole eggs, two egg yolks, and granulated sugar. You want it to be thick and pale. This process may take about 2 to 3 minutes—be patient!

Gradually pour the melted chocolate mixture into the egg mixture, whisking continuously. This tempering method prevents the eggs from scrambling.

Now, stir in the vanilla extract, instant espresso powder, kosher salt, cinnamon, and the optional dark rum or brandy. This is where the magic happens! The flavors combine beautifully.

Carefully fold in the flour until just combined. Take care not to overmix; you want to maintain air pockets for a light texture.

Evenly divide the batter among the prepared ramekins, filling each about 3/4 of the way full. The cakes will puff up while baking, so don’t overfill them.

Place the ramekins on a baking tray and bake in the preheated oven for 12-14 minutes. You’ll know they are ready when the edges feel firm, but the center remains soft.

Once baked, let the ramekins cool for about a minute. Carefully invert each one onto a plate, and the cake should slide right out. Serve immediately with a scoop of vanilla ice cream, a drizzle of sauce, and fresh strawberries.