Stuffed Swiss chard leaves

We followed this basic recipe for stuffed cabbage leaves: http://piglettedc.tumblr.com/post/122717650121/polish-stuffed-cabbage-leaves-galumpki-recipe However, we had to modify the recipe due to availability of ingredients. First, we used 10-11 rainbow Swiss chard leaves (2 bunches), with stems removed. We gently parboiled the leaves in slightly salted water with 1 tsp white vinegar (to preserve the bright colors), and we carefully fished them out and rinsed them in a colander under cool water. Second, for the filling, we used 1 lb minced beef and ¾ lb minced turkey. Third, instead of the 2 cups canned, chopped tomatoes, we used three chopped fresh hothouse tomatoes and added about 3 Tbsp tomato paste to the chicken broth mixture. Finally, for the 1:30 total cooking time, I would recommend leaving the foil on the casserole dish for 1 hour 15 mins (rather than one hour) and removing the foil only during the last 15 mins of cooking (rather than 30 mins). Swiss chard leaves are thinner and more delicate than red or white cabbage leaves, so they can break, dry out, and require special handling. (May 2017)