For the toasties, preheat the oven to 200°C. Spread the bread with butter and mustard.
Sprinkle over the cheddar. Bake for about 12 minutes or until melted and starting to crisp.
For the salsa, combine the oil, lemon juice, garlic and onion. Stir through the jalapenos (optional)coriander and avocado. Season with salt and pepper.
Serve the toasties topped with the salsa and extra coriander.
Tip:
Try a combination of mature cheddar and mozzarella.