Leaves ofSwiss chard, blancheduntil pliable and vibrant,make wrappers for parcels of a brown-rice filling enriched with ricotta;spoonfuls offresh tomato sauce givethe dish a garlicky nip.
Preheat oven to 400 degrees. Choose 12 large chard leaves (each should be about 10 inches long and 5 inches wide) or 24 smaller leaves; set aside. Coarsely chop enough of the remaining leaves to make 4 1/2 cups; reserve remaining leaves for another use. Bring a large pot of water to a boil; add a pinch of salt. Blanch whole leaves, 1 at a time, until tender and bright green, about 5 seconds. Lay flat on a baking sheet lined with paper towels to drain.
Melt butter with oil in a medium skillet over medium heat. Add leeks, scallions, 2 teaspoons salt, and 1/4 teaspoon pepper. Cook, stirring occasionally, until translucent, about 3 minutes. Add chopped chard, and cook, stirring occasionally, until chard has wilted, about 3 minutes more. Transfer to a medium bowl, and add pine nuts; let stand until cool. Stir in rice, cheeses, and breadcrumbs. Season with salt and pepper.
Place a blanched leaf facedown on a work surface. Cut out thickest part of stalk, about one-third of the way up leaf; slightly overlap the cut ends. If using smaller leaves, overlap 2 leaves so they are about 10 by 5 inches. Spoon 1/3 cup filling about one-third of the way up leaf. Fold bottom of leaf over mixture. Fold in sides. Roll to enclose filling completely, creating a 3-by-2-inch bundle. Repeat with remaining leaves and filling.
Transfer to a 9-by-13-inch baking dish. Tent with foil. Bake until heated through, about 15 minutes. Spoon warm sauce onto plates; serve 2 or 3 bundles per plate.