Turn on the oven to preheat it to 375 degrees Fahrenheit.
Take a big pot and cook lasagna till it starts getting crunchy inside. To cook it efficiently, remove it from the stove after 6 minutes. And drain out excess water.
Place the lasagna under the running cold water to stop the noodles from crumbling.
Take a saucepan and melt butter on the low heat.
Grease the casserole dish with the melted butter.
Take a small onion, white onion, or red onion and cut into small pieces. Add onion and sauté it.
Add flour to it. Keep whisking continuously for a few minutes to avoid lump formation. Don't overcook it to turn brown. Only cook it for a few minutes to avoid raw taste.
Add garlic, milk, and Knorr bouillon cube. Turn on the flame and stir the above ingredients at medium or high flame. Continue stirring to avoid bubbles.
Lower the heat flame to make a thick sauce properly. Add garlic powder and onion to the sauce.
When the sauce is cooked on the stove, take a large mixing bowl to add all the other ingredients.
Sprinkle some salt and pepper to taste the sauce mixture. Also, pour some ricotta cheese into it. Mix all vegetables into the sauce mixture. Take a small bowl and mix the remaining cheeses into it.
Take a pan and spread a layer of lasagna noodles over it. Add half of the cheese mixture and one-third vegetable mixture to it. Pour another layer of lasagna pasta over it and repeat till 3 layers of everything forms. In the end, pour some cheese with Shake'n Bake toppings. To cook pasta evenly, make sure it's completely covered with vegetable and sauce mixture. The uncovered area of pasta becomes crunchy and brown.
Bake it in the preheated oven for 25-45 minutes. If it's not bubbling even after 45 minutes, cook it for an hour till it starts bubbling. To make the top of the lasagna brown, you can turn on the broiler for 2 minutes.
Remove the baked lasagna from the oven and keep it aside for a few minutes before cooking it. Enjoy warm luscious lasagna.