Firstly make your base. In a food processor, blitz your biscuits into a crumb-like texture. If you don't have a food processor you can bash them with a rolling pin as well! You do want quite a fine consistency for this though.

Pour your melted butter into your crushed biscuits and mix together in a bowl.

Spoon your mixture into a loose bottom fluted tart tin (mine was 23cm across) and then using the back of a spoon and also your hands, press the mixture into the tin - both the base and up the sides. Try to get it as even and flat as you can - using a jar can make this easier.

Chill this in the fridge for around 30 minutes - 1 hour. Whilst this is happening you can sort out your filling.

On top of the caramel is a chocolate ganache - let's make this first. To make this, slice your dark and milk chocolate finely with a sharp knife - this helps it melt quicker when you pour the cream onto it. Place it in a heat-proof bowl.

In a small saucepan, heat your cream and butter - do this gently so the butter is fully melted and the cream is just about to reach boiling point (I stir mine a little so it doesn't stick to the bottom as it heats up).

Once heated, pour your cream mixture on top of your chopped chocolate (in its bowl) and leave it for about 5 minutes without stirring. After 5 minutes mix it all together so that it is combined, smooth and fully melted.

Remove your tart tin from the fridge. Mix your caramel briefly in the tin (or a small bowl) to loosen it - you can optionally add a pinch of salt here to make it salted caramel. Then pour it into your tart base and spread evenly.

Pour over your chocolate ganache mixture and spread evenly with a spatula or palette knife. Pop this back into the fridge for around 20-30 minutes - this will stop the M&M's sinking/disappearing into the ganache!

Next, add your M&Ms to the top.

Chill in the fridge for a 3-5 to allow the ganache to fully set.

Remove from the fridge a little earlier than you want to eat it (around 20 minutes) if the chocolate is quite firm - especially if you've left it in the fridge overnight. It might not need it though.

Slice up (the caramel does come out the sides a little bit as it's not a set caramel!) Enjoy with some vanilla ice cream!