Add rice, ground beef, ground pork and egg to the bowl with the cut onions. Season with salt and pepper. With your hands, mix well, then divide into portions. Working with a few leaves at a time, lay cabbage on a work surface, overlapping smaller leaves to form one larger leaf if necessary. Place a portion of the filling in the center of each. Fold bottom half of cabbage over filling, then fold in sides and roll up tightly. Transfer cabbage rolls, seam side down, to dutch oven. Top with remaining sauce. Cover dutch oven with lid and bake for about 40 minutes. Remove lid and bake until sauce is bubbling, about 10 minutes.
Enjoy! If you end up making some delicious stuffed cabbage, don't forget to post on social media and use hashtag #COOKFORUKRAINE.