Sauté the spinach in some olive oil until it shrinks down significantly, then season it with salt & pepper and let it cool. Once the spinach has cooled, use your hands to squeeze out any excess liquid, then stir it together with the ricotta cheese. Transfer the spinach & ricotta filling to a piping bag.
Fry the ground beef in some olive oil until it starts to brown, then add in the diced onions, minced garlic, and tomato paste. After everything has cooked briefly, add in the diced tomatoes, sugar, and herbs and bring the sauce to a gentle simmer. Let the meat sauce simmer for about 30 minutes and season with salt & pepper.
Heat a large pot filled with salted water on the stove. Cook the cannelloni for 3 minutes in the boiling water, then drain the noodles and run them under cold water to cool them off. Once the cannelloni noodles have been drained and cooled, return them to the large pot and stir in the grated parmesan.
Cut the cannelloni noodles in half and position them upright on a clean work surface. Pipe the spinach & ricotta filling into ⅓ of the halved cannelloni noodles, insert 2 cocktail sausages into another ⅓, and fill the final ⅓ with 2–3 mozzarella pearls each.
Grease an 11-inch springform pan and stand it up on its side. Fill the springform pan with the 3 different flavors of stuffed cannelloni, then return the springform pan to its original position. Pour the homemade meat sauce over the stuffed cannelloni and sprinkle shredded mozzarella on top. Transfer the springform pan to the oven and bake at 350°F for 45 minutes.
Once the honeycomb cannelloni bake has finished cooking, take it out of the oven and remove the ring from the springform pan. Garnish the honeycomb cannelloni bake with cherry tomatoes and chopped parsley.