For those unfamiliar with lentils, it's the orange/red lentils that cook down to a paste, and the brown, green, french ones that hold their shape. You can also find them sold whole, or often called 'football' lentils, or split. In Indian groceries you'll find lots of different types of dal, which are split pulses, and includes peas of all kinds and a type of chickpea
Once you get familiar with how the mix comes together throwing together different combos of cooked grains; dry grains like oats, flours, gluten, crumbs; ground flax; beans, lentils; tofu; tempeh; minced veggies; potatoes or even instant potatoes; and course what ever spices, salsa, mustards, and condiments that have lurked too long in the fridge
Cover the mix once it's right texture to make patties with and let sit in the fridge so all the components soak up the wet ones so they can hold their shape.
One thing I like a lot, esp as cold patties, is this quick and super cheap and easy pate-
one cup red lentils simmered in two cups water (and spices) on low heat for 10 to 15 minutes till soft.
Turn off heat and stir in 1/2 bulgar wheat, cover and let sit.
This makes great cold sandwich patties I like with all kinds of toppings, esp with cumin and pickles. I also use it as base for hot burgers by coating with flour and sauteing, or mixing with tomato soup or broth and frozen veggies for a quick soup.