I have given up green peppers because the red ones are sweeter, which makes these wonderful. My mom always included both ground beef and shrimp in her stuffed peppers, so I do too. I add the carrots for sweetness as well. I don't use an egg to bind the mixture, but cream instead, and it mellows everything out wonderfully. My grown children really do vie to take some home, so I always make a pretty large batch and freeze any if I can hide them before they all show up!
Preheat oven to 350 degrees. Find your largest skillet. (I use a 14 inch one!)
Cut each pepper in half length wise and remove any seeds & ribs. Bring 8 cups water to a boil in a large pot and blanch the peppers until tender-crisp, about 1-2 minutes. Drain and cool in ice bath to preserve color. Set aside.
Heat butter and oil in a large (12-14”) nonstick skillet over medium to medium high heat. Add celery, onions, carrots, garlic, and parsley and seasonings. Cook; stirring occasionally, until well softened - about 5-8 minutes. Crumble and add ground round, stirring occasionally until browned well. Drain the fat. Add the shrimp to the skillet and cook until pink, about 3-4 minutes.
Add bread crumbs and stir well then add cream and stir well again. Let cool. Mound stuffing generously into pepper halves. Sprinkle remaining breadcrumbs on top of each pepper. Bake at 350 for 30 minutes or until heated through.
Freeze any leftovers by wrapping each tightly in foil and putting inside Ziplock freezer bag(s). Can be thawed and reheated at 350 degrees for about 30-40 minutes.