Heat oven to 180C/160C fan/gas 4.
Tip the sugar, flour, cocoa and baking
powder into a large bowl. Whisk together
the eggs, vegetable oil and milk, then stir
together with the dry ingredients until
well combined. Add the milk chocolate
chips. Place cupcake cases into a 12-hole
bun tin. Divide the mixture between the
cases, then bake for 20 mins until risen
and cooked through. You can now leave
to cool and store for up to 2 days in an
Just before serving (either warm from
the oven or cold), arrange marshmallows
over the tops of the cakes. Heat grill to
medium and pop the cakes under it for
30 secs, watching all the time, just until
the marshmallows are lightly browned.
Remove and eat straight away.