1. Preheat oven to 350°F (180°C).
2. In a large skillet, sauté the onions in 1 Tbsp butter until just golden. Add spinach, salt, and garlic powder. Stir for 1 minute. Remove from flame and add cottage cheese and egg and mix well. Gently add the Parmesan cheese.
3. Stuff the raw cannelloni with the spinach-cheese mixture and place in a 9×13-inch pan. Pour the cream on top and sprinkle shredded cheese over everything.
4. Bake covered for 40 minutes. Uncover and continue baking until the cheese becomes golden, about 10–15 minutes.