Place your chopped bacon into a large skillet over medium heat, and cook, stirring often, until the bacon is crispy. Remove the bacon from the pan and place on a plate lined with paper towels to drain off any excess grease. Set aside until ready to use.
Add your sliced onions to the pan and season with salt; cook, stirring often, until the onions are caramelized. Taste and add additional salt if needed. (I like to cook my onions right in the bacon fat; just keep in mind you might not need all the fat. I normally discard about half and then cook my onions in the remaining fat. If you aren’t a fan of bacon fat, you can cook your onions in butter in a separate pan.)
Once the onions have finished cooking, remove them from the pan and set aside until ready to use.
Bring a large pot of water to a boil; once boiling, add your pasta of choice and cook to al denta according to the package directions. Drain your cooked pasta and rinse under cold water to keep the pasta from sticking; set aside until ready to use.
Preheat the oven to 350 degrees F. Reserve 1 cup of your shredded gouda cheese and 1 cup of your shredded white cheddar cheese.
In a large pot over medium heat, melt the stick of butter until it is completely melted and bubbly. Add the all-purpose flour and whisk until smooth. Next, slowly pour in your milk, whisking continuously.
Bring the mixture to a gentle simmer and continue whisking until it is thick enough to coat the back of a spoon. Add the spices and whisk to combine.
Remove the pan from the heat, add your remaining cheese(not the 2 cups you set aside) a little at a time, whisking between each addition until it is completely melted.
Once all the cheese has been added, add your cooked pasta and mix with a rubber spatula until the noodles are completely coated in the cheese sauce. Carefully pour the mac n cheese mixture into a 9 x 13 casserole dish. Be sure to scrape as much of the sauce out of the pan as you can!
Sprinkle the reserved cup of gouda cheese over the noodles, then layer your caramelized onions over the mac n cheese, followed by your crispy bacon. Finally, sprinkle the reserved white cheddar cheese over the top of the bacon and onions.
Place the mac n cheese into the oven and bake for 15-20 minutes or until the cheese on top is melted and the edges are bubbly. I like to switch my oven to broil, then broil until the melted cheese on top is golden brown, but that step is completely optional!
Remove from the oven and allow to cool for 5-10 minutes before serving.
Enjoy!