Step 1: Preheat your oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish.
Step 2: Bring a large pot of salted water to a boil and cook the pasta according to package directions until just shy of al dente. Drain, reserving 1/2 cup of pasta water.
Step 3: In a large skillet, heat olive oil over medium heat. Add the minced garlic and red pepper flakes, sautéing for 1 minute until fragrant.
Step 4: Add the chopped kale to the skillet and cook for 3-4 minutes until wilted and tender. Season with a pinch of salt.
Step 5: In a medium bowl, whisk together the pumpkin puree, milk (or cream), nutmeg, salt, and pepper until smooth.
Step 6: In the large pot used for the pasta, combine the cooked noodles, sautéed kale, and the pumpkin mixture. Stir in 1 cup of the cheddar cheese. If the sauce is too thick, add a bit of the reserved pasta water.
Step 7: Pour the mixture into the prepared baking dish. Top with the remaining cheddar, Parmesan, and panko breadcrumbs.
Step 8: Bake for 20-25 minutes until the cheese is melted and the top is golden brown and crispy.
Step 9: Let the pumpkin and kale pasta bake rest for 5 minutes before serving to allow the sauce to set.