Boil water to cook the egg noodles al dente.
In a pan, heat up oil to saute onion. Stir in the tuna flakes, then the peas to cook for a few minutes. Season with garlic powder, salt and black pepper.
In a small pot, melt butter, stir in flour then add milk. Keep stirring for a couple of minutes. Add 1 cup of the cheese. Stir until well incorporated. Preheat the oven to 350°
Drain the egg noodles. Place ‘em back in the pot. Combine the egg noodles and cheese sauce. Stir together. Pour into a casserole dish. Top evenly with the remaining cheese.
Sprinkle panko crumbs on top. Bake it in the oven for 20 minutes.