Peel a lot of garlic: I use about a third of a cup of bulbs per person. Fill a large pot with cold water, add salt and a little olive oil, cover, and put on a high heat. Put about a third of a stick of butter per person in a largish sauce pan (a two quart pan is fine for one or two servings). This should have heavy walls and hold heat well: I like my enameled ironware a lot.
Cover the butter pan, and put it on enough heat to melt it and bring it to a bubbling simmer without burning it (a little browning won't affect flavor much). Mince the garlic, with fresh basil if you have it. (A very little will flavor (and color!) the whole dish, but adding more won't have much effect. I use about a third of a supermarket bunch per serving.) Dump this on top of the melted butter and slosh it about, or stir; cover the sauce pan again and leave at lightly bubbling simmer.
Grate some cheese: parmesan, romana, or a blend. Two to four ounces per person. (This is much easier with a Cuisinart, as is mincing the garlic and basil.) When the pasta is ready, turn the heat on the butter up a bit and dump the drained spaghetti in. Dump the grated cheese on top, maybe grind some black pepper onto that. Stir until cheese is melted, serve.
Goes well with huge glasses of milk, or with red wine. Fattening.