Heat a large, heavy-bottomed skillet or dutch oven over high heat with a spritz of oil. Add onion, squash, half the salt, and the rosemary. Saute on high for about 5 minutes, stirring often. Turn the heat to medium, cover with a lid and cook for 10-15 minutes, stirring a few times. When the squash is starting to get fork-tender, add the vinegar and tomato paste and cook for another minute. Scoot the mixture to one side to make room for the beef. If your skillet isn’t large enough, you can remove the veggies for now.
Spray the open side of the pan with a little oil, and add the beef, the remaining salt, and the garlic. Using a meat masher, or wooden spoon, break apart the meat and cook for a few minutes until it’s browned and cooked thru.
Add the basil paste, canned tomatoes, and chopped kale to the pan and get everything combined. (If you had removed the squash, add that back in as well.) Cover and let that simmer/cook until the squash is as tender as you like, or about 5-10 minutes.
Blend together cottage cheese, milk, and parmesan. Pour the creamy mixture into the skillet and stir well. Top with mozzarella and cover to melt the cheese. OR, if your skillet is oven-safe, pop it in the oven to broil for a few minutes until the top is melted, bubbly, and starting to brown. Watch it closely!
Enjoy this in a bowl all by itself like a saucy lasagna, or very hearty soup. My family loves some crusty bread on the side of course! A simple green salad would be lovely if you want more going on!