01 - Cook the macaroni according to package directions until al dente. Drain thoroughly and set aside.
02 - In a large skillet over medium heat, cook the chopped bacon until crispy, approximately 6–8 minutes. Remove with a slotted spoon and drain on paper towels. Reserve 1 tablespoon of bacon fat for the sauce.
03 - In a large saucepan, melt the butter with the reserved bacon fat over medium heat. Add the flour and whisk constantly for 1 minute to form a roux.
04 - Gradually whisk in the milk until fully incorporated. Bring the mixture to a simmer and cook for 2–3 minutes until the sauce begins to thicken.
05 - Stir in the sharp cheddar, Parmesan cheese, garlic powder, onion powder, salt, and black pepper. Continue stirring until all cheese has melted and the sauce achieves a smooth consistency.
06 - Add the cooked macaroni and half of the crispy bacon to the cheese sauce. Stir thoroughly to ensure every piece of pasta is evenly coated.
07 - Gently fold in the diced avocado and fresh lemon juice, taking care not to mash the avocado pieces.
08 - Serve immediately while hot, topped with the remaining bacon and fresh chives as a garnish.