Preheat your oven to 200°C and line a baking tray with parchment paper.
In a bowl combine the softened butter, chopped garlic, chilli (or jalapeño), coriander and salt. Mix thoroughly until evenly combined and smooth.
Slice the ciabatta in half lengthways.
Spread the garlic butter generously over the cut sides of the bread, ensuring every edge is well coated.
Scatter the mozzarella and Red Leicester evenly over the buttered surface.
Arrange the pepperoni slices on top of the cheese in a single layer.
Place the bread halves onto the prepared tray and bake for 12–15 minutes, or until the edges are crisp, the cheese has melted fully and the pepperoni has lightly crisped.
Remove from the oven and allow to cool slightly before slicing.
Serve warm while the cheese is still gooey and melted.