Ricotta & Pesto Meat Loaf (Gluten-Free)

Like any casserole, this one is flexible. I've given you a good guideline for correct proportions, but add more or less salmon or tuna; more or less pasta; more or less peas – you get the picture. It will work and be delicious, regardless.
Lately I've been using canned salmon instead of tuna in this traditional recipe – Costco even carries wild Alaskan Sockeye Salmon (boneless) in the can, which boasts 410mg Omega 3s per serving! So this casserole is not only delicious, but it's a deliciously healthy one-dish meal the whole family will enjoy! Obviously, if you have leftover grilled salmon from the night before, it goes without saying (though I'll say it anyway, just in case!) that re-purposing those leftovers in this casserole would be the very best option!
I've also experimented wit...