Cook the Pasta: Boil a large pot of salted water. Cook macaroni until al dente, then drain. Reserve 1 cup of pasta water, rinse pasta under cold water, and set aside.
Make the Cheese Sauce: Melt butter in a Dutch oven or large skillet over medium heat. Add flour, whisking continuously for about 5 minutes until golden. Lower heat and gradually whisk in evaporated milk, chicken broth, and seasonings. Simmer for 5–10 minutes until slightly thickened.
Add Cheese and Pasta: Remove from heat and stir in cheddar and gouda cheese until melted. Mix in cooked macaroni, ensuring it's fully coated in the cheese sauce. If needed, add some reserved pasta water to adjust consistency.
Add Pulled Pork and BBQ Sauce: Warm the pulled pork separately, then layer it on top of the mac and cheese. Drizzle with BBQ sauce.
Serve and Enjoy: Garnish with crispy onions, crushed crackers, or green onions. Serve immediately!