Add peeled and diced potatoes to a pot and cover them with water. Bring the pot to a boil, then reduce the heat to a simmer, cover, and cook for 20 minutes or until the potatoes are tender when pierced with a fork. When the potatoes are done, drain them and rinse them to stop the cooking process.
Thaw the frozen peas by placing them in a strainer and setting them aside.
Grind the oats and cashews in a food processor. Set aside.
Heat a frying pan or skillet to medium and add the onions, carrots, and cauliflower. Stir constantly for 2-3 minutes to soften the vegetables. Add water, a tablespoon at a time, if they start to stick.
When the potatoes are cooled, mash them with curry powder, garlic powder, onion powder, cayenne pepper, and salt.
Mix in the cooked vegetables, peas, and chopped cilantro, then add the ground oats and cashews. Use your hands to mix the ingredients.
Form a ball to test the mixture. If it crumbles, continue mixing and kneading the ingredients. If they stay crumbly, add additional ground oats (you can also add a little chickpea flour or another flour binder). It also helps to chill the mixture or burger patties.
Preheat the oven to 400 F (200 C).
Line a baking tray with parchment paper and make 4 patties (smaller if you’re making appetizers), placing them on the tray.
Bake in the middle of the oven for 20 minutes until the patties start to brown. Flip and bake for another 10 minutes or until the burgers are brown, slightly crispy, and firm.