Tuna Penne Bake

2 c uncooked penne pasta
1 c frozen peas
1 can cream of mushroom soup
1/2 soup can of milk
2 cans tuna, drained and flaked
2 tbsp dijon mustard
1/2 c cheese, grated
1/2 c coarsley chopped onion
1/2 c chopped mushrooms

Prepare pasta according to package directions, omitting salt and adding peas for last 5 minutes of cooking.
Drain and set aside.
Combine in a baking didh soup, milk, tuna, mustard and half of cheese.
Gently stir in pasta, onions and mushrooms.
Top with remaining cheese.
Bake at 400 for 30 minutes.