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 chopped bacon until crispy, approximately 6–8 minutes. Remove with a slotted spoon and drain on paper towels. Reserve 1 tablespoon bacon fat.
03 - Melt butter with reserved bacon fat in a large saucepan over medium heat. Add flour and whisk constantly for 1 minute to form a smooth roux.
04 - Gradually whisk in milk until fully incorporated. Bring to a gentle simmer and cook for 2–3 minutes until sauce thickens slightly.
05 - Stir in cheddar, Parmesan, garlic powder, onion powder, salt, and pepper. Continue stirring until cheese melts completely and sauce becomes velvety smooth.
06 - Add cooked macaroni and half the crispy bacon to the cheese sauce. Stir thoroughly to coat all pasta evenly.
07 - Gently fold in diced avocado and lemon juice, taking care not to mash the avocado.
08 - Plate immediately, topping with remaining bacon and fresh chives if desired.