Potato and Cheese Pierogi

Name: Potato and Cheese Pierogi
Ingredients: 1 cup packed dill sprigs (tough stems removed); ½ cup olive oil; ½ tsp. fine salt; 2 small celery roots (about 1 lb. each), scrubbed and peeled; 3 Tbsp. olive oil; 1 tsp. fine salt, plus more; 1 lb. russet potatoes (about 2), peeled and coarsely chopped; 10½ oz. smoked twaróg, or farmer cheese; ½ cup (1¾ oz.) finely grated szafir, Džiugas, or parmesan cheese; 1 tsp. caraway seeds, plus more for serving; Freshly ground black pepper; Sour cream, for serving; 3½ cups (15¾ oz.) all-purpose flour, plus more for kneading; ¼ cup cold-pressed canola or extra-virgin olive oil; 1 tsp. fine salt