Do be careful while making the white sauce. In case you find the dish too dry, add a little water reserved while boiling the spaghetti (as suggested by Poorna in the comments). Now, we proceed.
Spaghetti in White Sauce
1 packet of spaghetti, boiled and kept aside
1 teaspoon garlic, minced
2 green chillies, chopped
5-6 chicken sausages, chopped
2 tablespoons vegetable oil
For the white sauce
2 tablespoons butter
1 tablespoon all-purpose flour
1 cup milk
2 cubes of processed cheese, grated (I used Amul cheese)
Salt and pepper to taste
Heat oil in a wok or kadai and pop in the minced garlic, chillies and the sausages. Once the garlic turns brown, tip in the cooked spaghetti and toss well. Remove from gas and keep the spaghetti aside.
Meanwhile, put up another pan on the gas and spoon in the butter. Now, add the flour into the sizzling butter and stir till it loses its raw smell. Take care not to burn the flour-butter mixture. Then, pour in the cup of milk and let it come to a gentle simmer. Smooth out the lumps, if any. Add the grated cheese and keep stirring till the cheese melts and is incorporated into the white sauce. Season with salt and pepper before taking it off the gas.
Now, pour the white sauce over the spaghetti and mix well so that it coats evenly. Check for seasonings and add more salt and pepper, if required. Garnish with generous sprinklings of oregano, basil and chilli flakes and serve hot.