Preheat oven to 375 degrees F (190 C).
Prep veggies, drain and dry tofu. Set aside.
Transfer tofu to a food processor, along with remaining omelet ingredients (seasoning, cornstarch) and mix to combine, scraping down sides as needed. Add just a touch of water to thin – 1-2 Tbsp at most. Set aside.
To a warm skillet over medium heat, add olive oil and the veggies. Season with salt and pepper and sauté to desired doneness. Set aside.
Remove skillet from heat and make sure it’s coated with enough oil so the omelet doesn’t stick. Add back 1/4 of the veggies and spoon on the omelet batter, spreading it gently with a spoon or rubber spatula, being careful not to tear or cause gaps. The thinner and more evenly you can spread it the better. So you may not end up using it all.
Cook over medium heat on the stove top for 5 minutes until the edges start to dry. Then place in oven and bake until dry and deep golden brown – 10-15 minutes. The longer it bakes the less soft/wet it will be, so if you prefer a more “well done” omelet, cook closer to 15 or more.
Using an oven mitt, in the last few minutes of cooking carefully add remaining veggies back on top of the omelet and cook another 1-2 minutes to warm through.
Carefully remove from oven with oven mitt and fold over gently with a spatula. If it doesn’t want to fold, you can serve it as a frittata or scramble!