In a blender or food processor, blend lentils, water, nutritional yeast, tomato paste, soy sauce, and garlic powder.
Transfer to a large mixing bowl and add the vital wheat gluten. Combine it thoroughly into the wet ingredients using a rubber spatula, then knead for 5-7 minutes using your hands.
Cut the dough ball in 4 or in 8 pieces, depending on how big you want the cutlets to be. Then use a rolling pin to roll out each section into 1cm ( ½-inch) thick steaks. The dough will be very tough and stretchy, but just keep working at it until you get your desired steak shapes.
Add several inches of water to a large pot with a steamer basket and bring to a boil. Put the steaks in the steamer basket and cover with a lid. Steam for 25 minutes, flipping the steaks halfway through so they steam evenly.
Set up your breading station. Add flour to the first bowl. In the second bowl, mix milk, flour, cornstarch, garlic and onion powders. Add the breadcrumbs to the third bowl. First coat each schnitzel in flour, then submerge it in batter. Next, coat evenly on both sides with breadcrumbs.
Cover the surface of a large non-stick skillet with olive oil and allow it to heat up for a few minutes over a medium-high heat.
Fry the cutlets for around 3-4 minutes on each side, until crispy and golden brown, then transfer to a flat surface covered with a kitchen towel to allow any excess oil to drip off.