Preheat the oven to 180°C fan. Butter individual ramekins or baking rings and place them on a baking tray.
Melt the chocolate and butter together until smooth. Allow to cool slightly.
In a separate bowl, whisk the eggs and sugar until combined.
Gradually whisk the chocolate mixture into the egg mixture.
Sift in the flour and salt, then gently fold until just combined.
Divide the batter between the molds, filling them three-quarters full.
Bake for approximately 10–12 minutes, depending on the size of the molds. The edges should be set while the centers remain soft and slightly wobbly.
Let stand for 1 minute, then serve immediately while the centers are still molten.
