In a 6 quart pot, boil water for pasta and add 1 tbsp of salt. Make elbow pasta according to box directions. Drain and set aside.
While the water is coming to a boil, grate your cheese(s) on a box grater and set aside.
In a blender, add the spinach leaves and milk. Blend until all the spinach leaves are completely smooth. Set aside.
To make the cheese sauce, start by making a roux: In the same pot you made the pasta, over medium heat, melt 2 tbsp butter.
When the butter is melted and foaming, add the 2 tbsp flour. Stir the flour until it's completely incorporated into the butter. Continue stirring for approximately 1 minute.
The roux will have a slightly nutty smell when you're supposed to add the milk. Don't brown the roux.
Carefully, slowly add the spinach/milk mixture while continuously whisking the roux/milk mixture.
Let the sauce thicken up and start to bubble stirring often.
Add the cheeses (monterey jack and parmesan) and mix in to thoroughly melt and incorporate. The cheese sauce should be thick, creamy and vivid green. Taste for seasonings. Add salt and pepper if needed. Remove from heat.
Add the drained elbow pasta to the cheese sauce and stir to combine thoroughly.
Pour the pasta into a serving bowl.
To make the "eyeballs": slice up either black or green olives and place the slices of olives over the mozzarella balls. Nestle the eyeballs into the green mac and cheese.
Serve with hot sauce (optional).
Looks gross but tastes delicious. Happy Halloween!!