2tablespoonsall-purpose flour, (18g) plus extra for dusting ramekins
powdered sugar, for dusting
Preheat the oven to 450°F (232°C).
Melt 1 tablespoon of butter in a microwave-safe dish for 30 seconds.
Brush melted butter on the inside of four 8-ounce ramekins.
Lightly coat with flour. Tap out the excess flour. Set the ramekins on a baking sheet.
In a double boiler, over simmering water, melt 4 ounces butter with the chocolate. Remove from heat and whisk together to combine.
In a medium-sized bowl, beat the eggs and egg yolks, sugar, and salt at high speed until thickened and pale, about 3 minutes.
Quickly fold chocolate into the egg mixture. Fold in the flour until combined.
Divide batter evenly into the prepared ramekins and bake on a sheet tray for 9 minutes, or until the sides of the cakes are firm, the tops are just slightly cracked, but the centers are soft and slightly jiggly.
Let the cakes cool in the ramekins for 1 minute.
Run a knife or small spatula along the sides of the ramekins a few times to release the cake.
Cover each ramekin with an inverted dessert plate. Carefully turn each one over, let stand for 10 seconds and then unmold. Use the spatula or knife to lift the corner of the ramekin and a gloved hand to lift and unmold the cake.