Preheat the oven to 425 degrees F. Toss the squash with the olive oil, salt and pepper. Spread it on a baking sheet and roast until tender and slightly caramelized on the edges, about 20 to 25 minutes.
While the squash is roasting, cook the pasta according to the directions. When finished, you can run it under cool water to stop it from cooking and also give it a quick spray of olive oil, tossing it, to keep it from sticking together.
Reduce the heat in the oven to 375 degrees F. Spray a 9x13 inch baking dish with nonstick spray.
Place the squash, tomatoes and garlic in a blender or food processor. Puree until smooth and creamy. Transfer the mixture to a large saucepan or skillet (make sure it’s large enough to add the ziti!) and add the milk. Heat over medium-low heat, stirring often.
Once the squash mixture is warmed, stir in most of the cheese. Add in small handfuls and stir until completely melted before adding more. I like to do about three quarters of the cheese, saving some for the top. Once the cheese is all melted, taste the sauce and season it more if needed. I like to start with 1/4 teaspoon of salt and pepper if needed.
Add the ziti to the squash sauce and toss well. Transfer all of the ziti into the baking dish. Scoop the ricotta in between the ziti - I like to do spoonfuls folded between the pasta all throughout the dish. Top the ziti with the remaining cheese. Top with the breadcrumbs.
Bake for 35 to 40 minutes, until golden and bubbly on top. Serve!