Preheat oven to 350°F.
Cook onion in butter for 5-6 minutes or until tender. Cool completely.
Combine all loaf ingredients in a bowl and mix well.
Place on a parchment lined pan and form into an 8"x 4" loaf.
Bake for 1 hour or until the inside of the loaf reaches 160°F.
Combine topping ingredients and spread over the top of the loaf during the last 20 minutes of cooking.
Rest 5-7 minutes before slicing.