If you have eaten aligot (cheesy mash) in its native region, the Auvergne, you may have found it somewhat gluey. This quality comes from the beating it has received in the pan, as the cook has combined the mashed potato and the cheese, over heat. The process releases a good deal of starch.
It is not unpleasant, and can be comforting. But if you want to avoid it, you can warm through the mixture in the oven.
The quantity of cheese may seem high. I often use more than this. For 2.
4 medium potatoes, peeled and cut into chunks
1 garlic clove
200g Cantal or similar cheese (Cheddar is fine)
Put the potatoes and garlic into lightly salted, cold water in a saucepan, bring to a boil, and simmer until soft. Drain, and allow to steam for a minute or two.
Heat the oven to gas mark 7/220C. Warm a gratin dish in it.
Put the butter into the hot saucepan. Pass the potato and garlic through a mouli-legumes into the pan (or slip the garlic from its skin, and mash it and the potato with a masher). Stir in the butter until melted. Stir in the cheese.
Tip the mixture into the gratin dish, cover with foil, and give it 10 minutes in the oven to warm through.