Tuna Shepherd's Pie

This was my mother's version of tuna casserole. The flavors blend as it bakes, and it's very different, and very delicious. Everyone I've ever served it to has loved it. I usually serve it with hot rolls and carrot and celery sticks (I even like it with whole berry cranberry sauce, but that could be what I'm used to from my childhood). Anyway, I really love this stuff.

• Ready In: 50 mins
• Serves: 4

Ingredients

• 1 (10 ounce) package  frozen peas and carrots
• 2 (7 ounce) cans solid white tuna or 2 (7 ounce) cans chunk tuna, well-drained (not chunk light)
• 1 (6 ounce) can  sliced mushroom pieces (optional)
• 1⁄4-1⁄3 cup mayonnaise
•  salt & pepper
• 4  cups  cooked mashed potatoes (see recipe note)
•  paprika

Directions

1. Preheat the oven to 350 and spray an 8x8" or 2 quart baking dish well with non-stick spray.
2. Using a colander, run the peas and carrots under hot water until separated and somewhat thawed; set aside.
3. In a bowl, flake the tuna well.
4. Add the mushrooms (if using) and the peas& carrots and toss together.
5. Add the mayonnaise and mix gently, but well; you don't want this too mayonnaisy; just enough to be able to bind the ingredients together.
6. Add salt and pepper to taste (you may not need too much salt as the tuna is salty to begin with).
7. Pat the tuna mixture into pan firmly and top evenly with the mashed potatoes.
8. With the back of a soup spoon, make little waves over the top of the potatoes by pressing the back of the spoon into the potatoes to make an indentation and then twisting up to make a little rising swirl; by doing this you get little peaks all over the top which brown nicely as it bakes and makes a great looking topping-- if the potatoes are hard to spread, warm them up a bit.
9. Sprinkle the top with paprika and bake for about 35 minutes, or until heated through, filling is bubbly around the edges, and the top is nicely golden brown.
10. Slice into squares and serve.
11. Note: The potatoes should be made with some butter or margarine as it makes for a better texture and helps it brown better.