Preheat the oven to 425 degrees. Toss the cauliflower florets with 2 tablespoons olive oil, salt, and pepper on a baking sheet. Roast for 20 to 25 minutes until the edges turn golden.

While the cauliflower roasts, make the sage pesto. Add the sage leaves, pine nuts, garlic cloves, 1/4 cup Parmesan, and remaining 1 tablespoon olive oil to a food processor. Blend until mostly smooth, then season with salt and pepper.

Cook the Italian sausage in a large skillet over medium heat, breaking it into crumbles, until browned and cooked through. Set aside.

Bring a large pot of salted water to a boil and cook the orecchiette according to package directions. Drain, reserving 1/2 cup pasta water.

Return the pasta to the pot. Stir in the sage pesto and a splash of pasta water to loosen the sauce. Add the cooked sausage and roasted cauliflower, then toss to combine. Top with the remaining Parmesan before serving.