Preheat oven to 375 degrees. Coat a 9” x 13” casserole dish with cooking spray and set aside.

Heat a large pot over medium-high heat. Place the spinach in a large colander and rinse well. Pour the spinach with water clinging to the leaves into the hot, dry pot and cook until wilted and bright green. Return the spinach to the colander and drain.

Fill the pot with salted water and bring to a boil over high heat. Add the pasta and cook al dente (for about 3 minutes less than the package called for).

While the pasta is cooking, squeeze the spinach then chop coarsely.

Drain al dente pasta in the colander and set aside.

In a large bowl, add diced onion, garlic powder, sour cream, warmed cream cheese, chopped spinach and chopped artichokes and stir to combine.

Add milk, Parmesan cheese, 1 cup of shredded pepper Jack cheese, salt and red pepper flakes and stir until well combined. Add drained pasta and fold until evenly distributed. Transfer mixture to prepared casserole dish and sprinkle top with remaining ½ cup shredded cheese.

Bake 30–35 minutes until hot and bubbly and beginning to brown on top. Remove from oven and allow to rest 5 minutes before serving.