Penne for One or Two

I made this last night from ingredients on hand. It tasted just like the free samples Trader Joe's was giving out last week.

1 1/2 cups whole wheat penne- measured dry
6 mushrooms sliced
1 stalk celery sliced
1/2 small onion chopped
small clove garlic minced
1 large Roma tomato, chopped, cored and seeds removed
1 cup Marinara sauce
2 handfuls of spinach - washed!
red pepper flakes about 1/4 teaspoon
1/2 teaspoon dried basil
salt to taste
olive oil 1 T.
Cook penne in boiling water to desired doneness, drain. In a 10" frying pan heat olive oil & saute mushrooms for 3-4 minutes, put in a small bowl and set aside. Put celery, onion and garlic in pan and cook until onion is translucent. Add tomato, basil and red pepper flakes, cook for a minute more. Add penne, marinara sauce and mushrooms, stir to mix and heat through. Put spinach on top, cover and heat until spinach is wilted.