1. Place an oven rack in the center of the over. Preheat the oven to 400. Butter an 8 x 8- inch glass baking dish and place it on a rimmed baking sheet. Set aside.
2. Bring a large pot of salted water to boil over a high heat. Remove the thick stem from the middle of each chard leaf. Cut each lead in half lengthwise. Trim the ends to make each leaf-half about 7 inches long and 4 inches wide. Add the leaves to the boiling eater and cook for 10 seconds. Remove the leaves and rinse with cold water. Drain on paper towel.
3. In medium bowl mix lentils, brown rice, ricotta cheese, 1/2 cup of Parmesan cheese, 1/3 cup of the olive oil, the arugula, mint, garlic, salt, and pepper.
4. Spoon 1 cup of the marinara sauce on the bottom of the prepared pan. Spoon a heaping 1/3 cup of the filling onto the end of each leaf and roll up like a burrito, tucking into sides as you go. Arrange the rolls, seam side down, in a single layer on top of the sauce. Spoon the remaining sauce of top and sprinkle the remaining 1/2 cup Parmesan cheese. Drizzle with the remaining 2 tablespoons olive oil.
5. Slide the baking sheet into the oven and bake 25 min,until the cheese begins to brown and the rolls are heated through. Cool for 5 min and serve