Preheat the oven to 190C/375F and spray a 12 hole muffin tin with cooking spray.

Make the crumb topping first: Place butter, sugar, flour and cocoa powder into a medium sized bowl and rub together with your fingers until you have a coarse bread crumb texture. Some larger and some smaller lumps of butter are great! Leave to one side.

Place chocolate chunks, flour, baking powder, bicarb, salt, sugar and ground coffee into a large bowl and stir until all of the chocolate is coated in flour.

Place cooled melted butter, vanilla, eggs and milk into a jug and lightly beat until there are no lumps of egg yolk.

Pour the milk mixture into your flour mixture and then gently stir until there are no lumps of flour visible. Don't beat otherwise you'll end up with rubbery muffins.

Divide the mixture between your muffin holes, filling each one level. I use a heaping 2tbsp cookie scoop to fill each one.

Sprinkle 1tbsp of the crumb topping onto each muffin and lightly press into the top with the back of a spoon or your hand.

Place in the oven for 15-20 minutes until risen and an inserted skewer into the centre comes out clean.

Leave to cool in the pan for at least 15 minutes before transferring to a wire rack to cool completely.

Once cool, Chocolate Coffee Crumb Muffins will keep in an airtight container, at room temperature, for 4 days.