01 - Boil elbow macaroni according to package directions until al dente. Drain thoroughly and set aside.
02 - Cook chopped bacon in a large skillet over medium heat for 6–8 minutes until crispy. Transfer to paper towels with a slotted spoon. Reserve 1 tablespoon bacon fat.
03 - Melt butter with reserved bacon fat in a large saucepan over medium heat. Whisk in flour and cook constantly for 1 minute to form a roux.
04 - Gradually whisk in milk until incorporated. Bring to a gentle simmer and cook for 2–3 minutes until sauce coats the back of a spoon.
05 - Stir in cheddar, Parmesan, garlic powder, onion powder, salt, and pepper. Continue stirring until completely melted and smooth.
06 - Add cooked macaroni and half the crispy bacon to the cheese sauce. Toss until pasta is evenly coated.
07 - Gently fold in diced avocado and lemon juice, being careful not to mash the avocado.
08 - Plate immediately and top with reserved bacon and fresh chives.