Since food prices have skyrocketed I've gone back to basics. I make a lot of mac and cheese. Here's the recipe I use from Emerils.com.
Em's Mac N' Cheese | Emerils.com
You can keep it simple without the cayenne or essence. The spices to make essence can get expensive but I've made this just using salt and pepper and it's excellent. Panko instead of bread crumbs makes a really crunchy topping.
The roux of butter and flour at the beginning is the challenge. You have to keep whisking so the flour won't burn. Then when you add the milk you have to keep whisking to keep our any lumps.
This is a good recipe to learn because a roux is the basis for a lot of sauces if you like to cook.
As for canned meats I don't measure anything but I add a couple of large spoonfuls of miracle whip (mayo), about a teaspoon or so of mustard, a small spoonful of pickle relish and salt and pepper. During the summer when I have fresh tomatoes I slice it from the top into eight sections, leaving them attached at the bottom to create a blossom and put a big scoop of the canned tuna or chicken salad on top. Delicious and refreshing!