Preheat the oven to 190°C/gas mark 5, line a 20cm square tin with baking parchment.
Melt the chocolate and butter in a heatproof bowl over a pan of simmering water.
Whisk the eggs until pale and fluffy. Add the Dark Muscovado Sugar and whisk until thick. Gently fold in the chocolate.
Sift in the flour and fold in until the mixture is smooth. Mix in the glacé cherries.
Pour the mixture into the prepared tin and bake for 30-35 minutes, until you see a paper-like crust on top. There should still be some movement in the centre of the tin.
Remove from the oven, leave to cool, then cut into squares.