Wash hands with soap and water.

Add the lentils to a medium saucepan and add water to cover by about an inch. Bring to a boil, then lower heat to a simmer and cook until tender, about 15 minutes. Drain and set aside.

Meanwhile, remove the excess water from the potato: you can either squeeze it by the handful, or put the entire pile on a clean tea towel and wring it out.

Crack the egg in a medium bowl and beat it lightly. Add the potato, cooked lentils, garlic, and green onion. Add cheese and hot sauce if you're using them. Add the salt and a good grinding of black pepper and stir until combined.

Heat a large skillet over medium heat, then add a generous drizzle of oil (1-2 tablespoons). Working in batches, so as not to crowd the pan, add clumps of the potato-lentil mixture (about the size of a golf ball or slightly larger works well), and flatten each as soon as it's in the pan, making them about a half inch thick.