Step 1

Heat 1 tbsp olive and oil and 1 tbsp butter in a Dutch Oven or large pot over medium heat. Add sliced onions and a big pinch of salt. Stir to combine, cover, and cook for 5 minutes.

Step 2

Remove lid, lower heat to medium low, and caramelize onions for 30-40 minutes, stirring occasionally. Halfway through, add a few sprigs of fresh thyme.

Step 3

Once caramelized, pour in sherry to deglaze the pan. Scrape the bottom of the pan with a wooden spoon as needed. Pour in the Worcestershire sauce. Cook for a few minutes until the liquid absorbs. Discard the thyme springs.

Step 4

Make the mac and cheese while the onions caramelize to save time. Cook pasta according to package instructions 1 minute less than al dente. Reserve about 1/2 a cup of pasta water.

Step 5

Meanwhile, melt 4 tbsp butter in a medium sauce pan over medium heat. Add the flour. Stir to combine and cook 2 minutes until starting to turn golden. Pour in whole milk and add dry mustard, cayenne, smoked paprika, garlic powder, and black pepper. Optionally, mix in better than bouillon beef paste. If omitting the paste, season to taste with salt. Add additional seasoning as desired. Turn heat to medium high and whisk, stirring constantly, for 3-5 minutes until thick.

Step 6

Turn off heat and add the freshly grated cheeses. Whisk until completely melted and smooth. Taste and add additional seasoning as desired.

Step 7

Add the cooked pasta to the cheese sauce and stir well to combine. Add a little pasta water as needed if the sauce is too thick. Then transfer the pasta to the pot of caramelized onions and combine everything together well.

Step 8

Preheat broiler.

Step 9

Melt 2 tbsp butter and stir in panko until well combined. Mix in cayenne, smoked paprika, garlic powder, and salt & pepper.

Step 10

Spoon caramelized onion mac and cheese equally into oven safe crocks. Evenly divide the panko mixture on top of each crock. Finally, evenly sprinkle additional shredded cheddar, gruyere, and parmesan cheese on top. Season as desired with black pepper. Broil for 3-5 minutes until golden and bubbly. Serve immediately.