- Preheat the oven: To 425°F (220°C).
Generously butter 4 mini bundt pans and dust with cocoa powder.
- Melt butter and chocolate: In a heatproof bowl over simmering water or in the microwave until smooth. Let cool slightly.
- Whisk together eggs, yolks, sugar, and vanilla: Until light and thick.
- Combine chocolate mixture with egg mixture: Gently fold in flour and salt until just combined.
- Pour batter into pans: Fill each about 3/4 full.
- Bake: For 10–12 minutes until edges are set but centers are soft.
- Cool and serve: Invert onto plates and enjoy warm with desired toppings.