Steps
1. Preheat the oven to 425°F (220°C). Grease and lightly flour a ramekin or small oven-safe dish.
2. In a microwave-safe bowl, melt the butter and dark chocolate together, stirring until smooth.
3. In a separate bowl, whisk together the granulated sugar and egg until well combined.
4. Gradually add the melted chocolate mixture to the sugar and egg mixture, stirring constantly.
5. Slowly mix in the flour, salt, milk, and vanilla extract until a smooth batter forms.
6. Pour the batter into the prepared ramekin or dish.
7. Place the ramekin or dish onto a baking sheet and bake for 10-12 minutes, or until the edges are set but the center is still slightly jiggly.
8. Remove from the oven and let it cool for a minute. Carefully invert the cake onto a plate and gently tap the bottom to release the cake.
9. Serve warm and enjoy the molten chocolate lava cake!