Fill a pot with 2.5 quarts of water and add 2 tablespoons of kosher salt. Bring the water to boil. Add the elbow macaroni to the boiling water. Cook the pasta al dente–follow package directions, minus 1 or 2 minutes. The pasta will cook further when it is in the oven. As the pasta is boiling, fill a bowl 3/4 of the way full with ice water.
Drain the cooked pasta. Transfer the pasta to the bowl with ice water. Let the pasta sit in the ice for 1 or 2 minutes before draining again. This stops the pasta from cooking further and prevents it from getting mushy or sticking to each other.
Peel the sweet potatoes and dice them into 1-inch cubes. Add the cubed sweet potatoes to a large saucepan and fill it with enough water to cover the sweet potatoes by about 1 inch. Bring the water to boil, then simmer for about 8 to 10 minutes, until the sweet potatoes are fork tender. (See note 3 for Instant Pot cooking method.)
Drain and transfer sweet potatoes to a bowl to mash. Do this while the sweet potatoes are still hot. Add the garlic powder, paprika, and cayenne to the mashed potatoes, and stir to combine.
Preheat the oven to 375ºF (190ºC). Position an oven rack to the center position. Lightly grease a 9x13 baking dish with olive oil. Set the baking dish aside.
Melt 3 tablespoons butter in a large sauté pan or a pot over medium heat. Add the flour and stir to combine. In about 2 minutes, the butter and flour will bubble and puff up, turning into a light sauce (roux).
Pour in half of the milk into the pan and whisk for about 1 minute to break up the clumps of flour. You won’t be able to break up the flour completely, and that’s okay. Add the remaining milk and 1 1/2 teaspoons salt and cook for about 5 to 7 minutes, stirring occasionally. The sauce should now be thick, like chowder.
Add the mashed sweet potatoes and stir until well combined. Turn off the heat.
Set 1 cup of shredded cheese to the side for topping. Then, add the remaining shredded cheese to the sauce. The cheese doesn’t need to melt completely. Add the pasta, sliced olives, and kale and stir to combine (see note 4).
Pour the mac and cheese into the greased baking dish. Sprinkle remaining shredded cheese over the pasta.
To make the topping, mix the melted butter with panko breadcrumbs. Sprinkle the panko over the mac and cheese.
Bake for 15 to 20 minutes, until the cheese starts to bubble on the edges. Then, broil the mac and cheese for 3 to 4 minutes, until the top is golden brown (see note 5).
Remove the mac and cheese from the oven. Sprinkle chopped parsley over the mac and cheese for garnish. Serve while the mac and cheese is still warm. Drizzle with chili oil, if you like.
You can substitute baby kale with chopped kale, baby spinach, or chopped swiss chard.
I can usually find panko in the Asian section of most supermarkets. You can also find panko in Asian supermarkets.
Cook sweet potatoes in the Instant Pot: Add 1 cup water to the Instant Pot, then add a steamer basket to the pot. Transfer the cubed sweet potatoes into the steamer basket. Cover the pot and press the “MANUAL” button. Cook on high for 8 minutes. Let the pressure naturally release for 10 minutes. Release any residual pressure and uncover the Instant Pot. Stick a fork into the sweet potatoes to check to see if they are tender. Transfer the sweet potatoes to a bowl to mash.
If you don’t have a big enough sauté pan for this, toss the pasta, California Black Ripe Olives, and baby kale in a large mixing bowl. Prepare the sauce in the pan and pour the sauce over the mixing bowl. Stir until everything is incorporated before transferring to the baking dish.
If you don’t have a broiler, you can bake the mac and cheese at 350ºF for about 25 to 30 minutes, until the top is lightly golden brown and the cheese is bubbling on the sides. You want the temperature to be lower so that the kale doesn’t overcook and turn brownish.
Make-ahead directions: You can make the mac and cheese the day before. Follow the directions up to step 11. Cover the pan and refrigerate overnight. Add the panko to the mac and cheese when you are ready to bake. You may need to add a few minutes to the total baking time.