1. 1. Preheat the oven to 425°F (220°C) and grease ramekins with butter and cocoa powder.

2. 2. In a microwave-safe bowl, melt butter and chocolate together, stirring until smooth.

3. 3. In a separate bowl, whisk together eggs, sugar, and vanilla extract until well combined.

4. 4. Gently fold the chocolate mixture into the egg mixture, then add flour and salt, mixing until just combined.

5. 5. Divide the batter evenly among the prepared ramekins.

6. 6. Bake for 12-14 minutes until the edges are set but the center is still gooey.

7. 7. Let cool for a few minutes before unmolding onto plates.

8. 8. Serve warm with a dusting of powdered sugar or a scoop of vanilla ice cream.