Rinse salmon filets and spread them out on a sheet pan or cutting board and pat dry. Season filets lightly with some salt and pepper.
Preheat the air fryer to 350F / 190C. (It should take about 5 minutes for the air fryer to heat up.)
Transfer salmon to the basket of the air fryer.
Cook salmon for 5 minutes to get it started cooking.
While salmon is cooking, melt butter in the microwave, ~1 minute. Mix butter with mustard, maple syrup, soy sauce, panko, and parsley.
Working carefully (the basket of the air fryer will be hot), spoon panko crust over the top of the salmon.
Keep cooking salmon until it flakes easily with a fork and the crust is golden brown, 4 to 10 minutes more (depending on thickness).
Serve immediately.
