1Slice the leek into julienne strips and sauté in a pan with a drizzle of olive oil and the rosemary sprig. Remove the rosemary once it has infused the oil.
2Add the diced squash, season with salt and pepper, and cover with water. Cook until the squash is soft, then blend into a light sauce.
3Blend the parmigiano cheese with the basil leaves until you achieve a thick consistency.
4Cook the fusilli al dente, drain, and toss with the light sauce.
5Plate the fusilli and garnish with the basil and parmigiano on top.