Preheat the oven to 450°F.
Melt butter and chocolate in a microwave-safe bowl in 15-second intervals until just melted. Mix and set aside.
In a separate bowl, whisk the egg and sugar for 5-7 minutes until light, thick, and frothy.
Gently combine the melted butter and chocolate mixture with the egg mixture.
Sift in the flour and salt, gently whisking in a folding motion until just combined.
Generously coat an 8oz ramekin with softened butter, add 1 tsp of cocoa powder, tap, and rotate to spread. Tap out the excess.
Pour the batter into the ramekin, leaving a little room for the cake to rise.
Bake for about 10-11 minutes, keeping an eye on it. The cake should be firmer on the sides but slightly jiggly in the center.
Let the cake rest in the ramekin for 1 minute. Release the edges with a butter knife and carefully turn it out.
Serve with vanilla ice cream and savor the moment!