Preheat oven to 180º C, fan 160º C
Grease a 12 hole muffin tray
Melt dark chocolate with butter, stir until smooth, and cool for 5 minutes
Mix eggs, sugar and vanilla extract in a large bowl
Whisk until frothy
Gently mix the melted chocolate into the egg mixture
Add the almond flour
Fold together the almond flour and chocolate-egg mixture
Divide mixture evenly between the 12 muffin tray holes
Bake at 180º C, fan 160º C, for 12 minutes
Remove tray from the oven
Top each part-baked brownie with a 5 gram lump of milk chocolate (or mini-egg)
Press milk chocolate down gently
Bake for a further 5 minutes until the milk chocolate has started to soften and brownies are just firm to the touch
Remove tray from oven and leave brownies to cool for about 10 minutes
Transfer brownies to a wire rack
Eat warm or cold