Cut pork and veal into thin slices, then into 1-inch pieces. Keep them separate.
Cook the pork in a small skillet with the butter over medium low, turning often, for 5 minutes.
Add the veal and brown it on both sides for 1 1/2 minutes or less. Season with salt and pepper, stir to coat, then remove all the meat with a slotted spoon, leaving the fat behind.
When cool enough to handle, chop pork and veal together to a grainy, slightly coarse texture. A food processor is fine, but do not puree it.
Put the chopped meat in a bowl and add mortadella, ricotta, grated cheese, egg yolk, and a tiny grating of nutmeg (about 1/8 tsp). Mix thoroughly. Taste and adjust salt and pepper.
Make green pasta dough by the machine method or hand-rolled method. Cut, stuff, and shape tortellini. When boiling, add 1 tbsp olive oil to the water.