The key here, I think, is to use a nice sharp cheddar. In this way, instead of blanketing and muffling the broccoli and apple, the cheese sauce adds a layer of contrast. There’s simply nothing like a good mature cheddar, the crumble and smoothness, the pungent nutiness with a faint tang of grass. It’s good stuff, and it does the other members of the gratin nothing but favors.
Broccoli Cheddar and Apple Gratin (serves 4-6)