Steps
1. Preheat the oven to 425°F (220°C) and grease a ramekin with butter.
2. In a microwave-safe bowl, melt the butter and chocolate chips together in 30-second intervals until fully melted and smooth.
3. In a separate bowl, whisk together the sugar, egg, and vanilla extract.
4. Slowly pour the melted chocolate mixture into the sugar mixture, stirring continuously.
5. Add the flour and salt to the batter and mix until just combined.
6. Pour the batter into the greased ramekin and place it on a baking sheet.
7. Bake for 10-12 minutes or until the edges are set but the center is still soft and jiggly.
8. Remove the ramekin from the oven and let it cool for a minute.
9. Carefully invert the ramekin onto a serving plate, tapping gently to release the cake.
10. Dust with powdered sugar and serve immediately.