Omit the salt if your stock is salty. You can use 4 1/4 cups water plus 4 bouillon cubes in place of the stock and water in this recipe.
Plain brown or green lentils can be used instead of French lentils.
Use anywhere between 1/2 cup to 2 cups of any cheese.
If you use a smaller baking dish, you'll be approaching the top of the dish, so put a pan under it so it doesn't spill in the oven. The 9x13-inch pan works great.