Instructions

• Preheat oven to 450°F (230°C) and position a rack in the center.
• Prepare four 4-ounce ramekins: butter the insides with the extra butter, cut parchment rounds to fit the bottoms and press them into the ramekins, butter the top of each parchment round, then dust the insides of the ramekins with a little of the extra flour and tap out the excess. Set the ramekins aside.
• Place the chopped chocolate and 1 stick butter in a microwave-safe bowl and melt gently in short bursts, stirring frequently, until smooth. (Alternatively, melt together over a double boiler.) Let the chocolate mixture cool until just warm.
• In a mixing bowl, beat the 2 eggs, 2 egg yolks, and 1/4 cup sugar with a mixer or whisk until the mixture is pale and slightly thickened.
• Temper the eggs by adding one small spoonful of the warm chocolate mixture to the egg mixture and whisking to combine, then add the remaining chocolate and stir until fully incorporated.
• Sprinkle the 2 teaspoons flour over the batter and fold or mix just until the flour disappears and the batter is uniform. Do not overmix.
• Divide the batter evenly among the prepared ramekins.
• Place the filled ramekins on a baking sheet and bake until the edges are set but the centers remain soft and slightly jiggly, about 6–10 minutes (times vary by oven; many take about 9 minutes).
• Remove the baking sheet from the oven and let the ramekins sit 1–2 minutes. Run a thin knife or metal spatula around the inside edge of each ramekin to loosen the cakes.
• Invert each ramekin onto a serving plate and gently lift it off; if a cake does not release, wait another 30–60 seconds and try again. Serve immediately.