In a large mixing bowl, combine the breadcrumbs, half & half, and egg and mix to combine. Sit for 5 minutes. Add the remaining ingredients and mix well by hand. Using a 1/4 cup scoop, portion the mixture and roll into balls. Place on a parchment-lined baking sheet.

Set an oven broiler to high and arrange the top rack to be in the middle of the oven. Broil for 10-12 minutes, until the tops are browned. At this point, you can cool and freeze the meatballs, or transfer to the sauce to simmer.

In a large skillet, braiser, or a dutch oven, heat the olive oil over medium heat. Add the onion and garlic and cook for 2-3 minutes, stirring often, until the onions are soft. Add the crushed red pepper and cook for one minute more. Then, add the crushed tomatoes, tomato puree, and sugar. Bring to a light simmer and add the basil leaves. Season with salt and pepper.

Add the meatballs in a single layer and toss to coat with the sauce. Cover, reduce heat to low, and simmer for 45 minutes. Taste the sauce for seasoning and season as necessary. Toss with spaghetti and serve topped with more fresh basil and parmesan.