This is a bit difficult because you have to cook four components and combine them, so logistics is complicated. They are: fried vegetables + al dente cooked spaghetti + scrambled egg + tofu.
One method is to scramble the egg before hand and set aside. Fry the tofu and keep it warm in the oven. Boil the noodles and keep ready. Fry the vegetables, add the noodles, add the egg, serve with the tofu.
You will need soy sauce and oyster sauce. This recipes is for 2 or 3 servings. Cook enough noodles for that, or scale the quantities. It is supposed to be mostly noodles.
To cook the eggs: mix a small amount of corn starch slurry into two eggs. Wisk. Pan fry in a large table spoon of oil. Use salt and pepper.
To cook tofu: take a block of tofu and slice it through the midline of the shortest dimension - so you have two large blocks, each 1/2 a block thick.
Try to dry these out a bit with a towel but do not press hard. Leave the tofu alone. Dust each piece thoroughly with corn starch. Fry in a shallow layer of oil: slowly, to drive off the moisture, one side at a time, and until it is crispy and golden brown/burnt on each surface. Remove to a plate and keep warm in the oven. No seasoning at this stage.
To cook noodles: try not to overcook, as the noodles will be cooked slightly more later. Drain and set aside.
To cook vegetables: Take small amount of all vegetables (<1/4 cup, finely chopped of each): onions, carrots, green onions, mushrooms, cabbage. Fry onions, add a teaspoon of chopped ginger. When onions are started, add carrots, then mushrooms and green onion (white part). When all else is softened, add cabbage and wait for it to wilt. Now add scrambled eggs and 1 Tsp soy sauce, 1 Tbs of oyster sauce (really key!). Stir in cooked noodles. Top with green onion (green part). Put on serving dish but keep frying pan hot.
Put tofu back in hot frying pan for 45 sec while you pour a small amount of soy sauce over the two pieces. Serve over/beside the noodles.