Preheat the oven to 400F and toss together the butternut squash, salt, pepper, 1 tbsp olive oil and paprika in a sheet pan. Bake for about 20-30 mins, till the squash is roasted.
Meanwhile, boil salted water in a sauce pan and cook the orzo in it to al dente. Reserve a cup of the pasta water. Drain the orzo and keep aside.
Cut the cherry tomatoes in half and keep aside.
Heat the remaining 1 tbsp olive oil in a pan and add the minced garlic and cherry tomatoes to it. Toss quickly for a couple of minutes till the tomatoes soften a little.
Transfer the orzo to a large serving bowl. Add the roasted butternut squash, cherry tomatoes, walnuts, lemon zest and juice, more salt and freshly crushed black pepper, about 1/2 cup of the pasta water, parmesan and the parsley. Toss well and seve warm.