To a 6-quart Instant Pot add pork shoulder, yellow onion, and ginger ale. Set manual time for 75 minutes on high.
Pull the pork roast out of the Instant Pot, add to a large plate and shred with two forks. Pour out the juice from the Instant Pot and add shredded pork back to the Instant Pot. Add in Stubb’s Original Bar-B-Q Sauce and stir. Cover to keep warm while you prepare the mac and cheese.
Preheat the oven to 350 degrees F and spray a 9×13 casserole dish with non-stick spray.
Bring a large pot filled with salted water to a boil over high heat.
Add in elbow macaroni and cook just until al dente following box directions.
Drain pasta and set it aside while you prepare the cheese sauce.
Add a large skillet over medium heat and add butter. Once the butter is melted whisk in flour. Slowly whisk in milk until smooth. Reduce the heat to low and whisk slowly until the sauce becomes thick and creamy. Stir in the shredded cheese and stir until completely melted.Turn off the heat and stir in macaroni.
Add macaroni and cheese to the prepared dish and top with pulled pork. Sprinkle on a little extra cheese if desired.
Bake for about 15 minutes just to help warm the mixture through.
Drizzle with extra Stubb’s Original Bar-B-Q Sauce. Enjoy!