PREP: Open the tuna and drain thoroughly. Fluff with a fork and set aside.
ADD EVERYTHING TO A SKILLET: In a large 10-inch nonstick skillet (3-quart; 2.8-liter), pour in 2 cups of uncooked pasta; the drained tuna; milk, water, butter, and seasonings (dry mustard powder, paprika, garlic powder). Add salt and pepper to taste; I add 1 teaspoon fine sea salt and ¼ teaspoon pepper.
BOIL: Bring to a boil over high heat, stir, and then cover with the lid. Reduce the heat to low or just a few notches above low to keep the mixture lightly bubbling but not at a rolling boil.
SIMMER: Allow to simmer until the pasta is completely cooked through and the liquid has evaporated (about 10-15 minutes, depending on your stovetop heat; check at 10 minutes). During the cooking time, stir the ingredients every 5-7 minutes to keep the pasta from sticking to the bottom. While the pasta is simmering, grate the cheese.
ADD CHEESE AND PEAS: Once the liquid is absorbed, remove the skillet from the heat. Stir in the grated Cheddar cheese until melted. Once melted, add in the frozen peas and stir to warm through.
ENJOY: Taste and adjust for any additional seasonings needed. Add salt and pepper to taste as well as any other additional seasonings (more garlic powder, paprika, etc.). Enjoy while hot. If desired, garnish individual plates and freshly chopped parsley and/or a drizzle of hot sauce.
Notes
Note 1: Pasta: Check the cooking directions and make sure the pasta you use can be cooked in 6-8 minutes.Note 2: Milk: Skim milk, soy milk, almond milk, etc. were not successful in my recipe testing. Regular dairy milk needs to be used here; I recommend whole milk, but 1% or 2% will work (not skim).Note 3: Cheese: Cheese is a big part of this dish so choose a very flavorful cheese you love. I use and recommend sharp or extra-sharp Cheddar cheese. I recommend freshly grated, as the bagged cheeses can create a waxy texture when melted.