Heat the oven to 180. Add the cheddar, Grolsch, garlic, mustard, thyme and salt to a blender and blend until combined but still coarse.
Halve the bread lengthways and then halve each slice to make four equal slices. Spread the cheesy mixture over bread and place in the oven to cook until the cheese has melted and started to brown (about 10 minutes).
Meanwhile, make the caramelised onions. Add all the ingredients to a pot over low heat and cook until all the sugar has dissolved and the onions have cooked down completely.
Serve on top of the cheese melts.
Recipe by Grolsch. For more pairing ideas, visit our dedicated Grolsch page.