This is a favorite in my family. Growing up we used chicken or turkey depending on what was around the house.
To make just have the turkey or chicken shreded up some. Easier to consume that way. I start off with a rue. About a stick of butter and 4 tablespoons flour. Melt the butter. Mix the flour into the butter. Let cook about 2 minutes. Slowly add either some stock or some water about 2 cups into the mix. If it's took thick for you still, slowly add more water. If too thin, add some more flour.
Don't let the mixture boil, but let it get hot. Then add in the turkey and 1 16 oz bag of frozen peas. Cook until the turkey and the peas are heated throughly.
While making, start up on some toast. We serve everyone 2 pieces of toast, and then smoother the toast. Sometime, I will use biscuits. I try to make up some home made bread the day or two before, and that is really good to use. I sometimes do have to hide the bread, so it will last that day or two.