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 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, whisking constantly for 1 minute to form a smooth paste.
04 - Gradually whisk in milk until fully incorporated. Bring to a simmer and cook for 2–3 minutes until slightly thickened.
05 - Stir in cheddar, Parmesan, garlic powder, onion powder, salt, and pepper. Continue stirring until cheese is completely melted and sauce is velvety smooth.
06 - Add cooked macaroni and half the bacon to the cheese sauce. Stir thoroughly to ensure every piece is evenly coated.
07 - Gently fold in diced avocado and lemon juice, being careful not to mash the avocado.
08 - Serve immediately topped with remaining crispy bacon and fresh chives if desired.