In a 5- to 6-quart pan, combine oil, onions and garlic; stir over high heat
until onions are tinged with brown, about 8 minutes. Stir in curry powder. Add
broth and bring to a boil.
Sort and discard debris from lentils. Rinse lentils, then drain. Add to
broth. Cover and simmer until lentils are tender to bite, 30 to 35 minutes.
If mixture is soupy, boil uncovered until liquid is just below surface of lentils,
Pour lentils into a shallow 3-quart casserole. (If making ahead, cool, cover
and chill up to 1 day.) Bake, covered, at 350 degrees F until lentils absorb
most of the liquid, about 30 minutes (if chilled, 1 to 1 1/4 hours).
Uncover and sprinkle with cheese. Bake until cheese melts, about 5 minutes.