Preheat the oven to 375 degrees F (190 degrees C). Grease a large cast-iron skillet, casserole pan, or a 9x13-inch baking dish, and set it aside.
Bring a large pot of salted water to a boil. Add the Penne Pasta (12 ounce) and cook, following the package directions, until 2 minutes shy of al dente. The pasta should still have a bite to it. Drain, and shake out all the water.
Heat the Coconut Oil (2 tablespoon) in a large non-stick skillet over medium heat. Sauté the Shallot (2) until soft, about 3 minutes.
Add the Garlic (2 clove) and Crushed Red Pepper Flakes (1/4 teaspoon) and cook for another minute.
Sprinkle in the Gluten-Free All-Purpose Flour (2 tablespoon) and stir to coat. Cook for a minute.
Whisk in the Sea Salt (1/2 teaspoon), Almond Milk (1 cup), and Chicken Broth (1 cup). Simmer until thickened enough to coat the back of a spoon, about 4 minutes.
Carefully fold in the Fresh Baby Spinach (10 ounce) in two batches. Cook until wilted, 2 minutes.
Add the White Cheddar Cheese (1 cup) and pasta and stir until very well coated in the spinach mixture.
Transfer to the prepared dish and spread in an even layer. Sprinkle with the Shredded Parmesan Cheese (1/4 cup).
Bake the mac ‘n cheese until melted and crisp on the top, about 15 minutes. You can pop it under the broiler for a few minutes if you want the top to get extra brown and crunchy.