Bring a large pot of water to a boil. Add pierogies; cook until they float to the top and filling is hot, 5 to 7 minutes. Drain.
Preheat oven to 350 degrees F (175 degrees C). Grease a large casserole dish with butter.
Combine onion and 1 tablespoon water in a large skillet over medium heat; cook and stir until onion is translucent, about 5 minutes. Stir in sausage; cook until warmed through and crisp around the edges, about 5 minutes. Add cabbage; cook and stir until starting to soften, 5 to 10 minutes.
Whisk 1 cup water, yogurt, tomato paste, dill, and lemon pepper together in a small bowl. Pour over the kielbasa-cabbage mixture in the skillet; cook until flavors combine, 10 to 15 minutes.
Place pierogies in the prepared baking dish; pour kielbasa-cabbage mixture on top. Cover baking dish with aluminum foil.
Bake in the preheated oven until hot and bubbly, about 30 minutes.