Remove the chard leaves from the stems. Cut the leaves into bite-sized pieces and set aside. Finely chop the chard stems.
Place a skillet over medium heat. Add the butter and olive oil along with the diced onions and chard stems. Season with a pinch of kosher salt. Sauté for 5 to 7 minutes, until the stems are tender. Add the minced garlic and cook for another minute. Remove from the heat and allow the stems to cool down.
In a mixing bowl combine the milk and eggs. Whisk together. Add the flour, baking powder, and 1 tsp kosher salt. Whisk until it becomes a smooth batter. Add the chopped chard leaves and the cooled stems along with the fresh dill and grated mozzarella and parmesan cheeses. Stir the mixture together until fully combined.
Place a rack on a baking sheet and have ready to drain the fritters. In a wide skillet, add enough vegetable to cover the bottom of the pan, about 1/8 inch deep. Place over medium heat.
Drop a spoonful of the fritter batter into the hot oil. Gently spread the batter out to create a flat fritter, about 2 inches in diameter. Add 3 or 4 more to the pan. Allow the fritters to fry until the bottoms are golden brown, about 4 to 5 minutes. Lower the heat if they brown too quickly.
The fritters may stick to the pan initially but as the fritters brown, they should release from the pan with relative ease. Carefully flip the fritters over and cook for another couple of minutes until the browned on the other side.
Transfer the cooked fritters to the rack to drain. Repeat with the remaining batter until all the fritters are cooked.
Yogurt Dipping Sauce
In a small bowl, combine the yogurt, lemon juice, olive oil, fresh chopped dill, minced garlic, 1/2 tsp kosher salt, and a pinch of pepper. Stir together. Refrigerate until ready to serve.
To Serve
Arrange the chard fritters on a serving platter. Serve the fritters with the yogurt sauce and enjoy!
Notes
*Should equal around 2 cups chopped stems and 4 cups loosely packed chopped leaves