Wash and sort the spinach, remove the coarse stalks. Place dripping wet in a large saucepan and let collapse, covered, over medium heat. Then lift into a sieve with a slotted spoon and drain. Squeeze out additional moisture with a wooden spoon. Wash the dill, shake dry and chop, save some tips for garnish. Mix the rest with the spinach. Season to taste with salt and pepper.
Preheat oven to 175 degrees. Rub a baking dish with butter. Mix the quark, eggs and flour in a bowl. Grate the cheese or cut it into small cubes and stir into the quark together with the spinach. Put the mixture in the baking dish and bake in the oven for about 50 minutes. Garnish with dill.