Melt butter in large saucepan on medium heat. Whisk in flour, cook and stir for 1 minute. Gradually stir in milk, whisking constantly until thickened. Reduce heat to low. Add the 80ml RedHot Sauce and cheese, stirring until melted. Remove from heat. Set aside 125ml cheese sauce and place in small microwave-safe bowl, set aside.
Add 1 egg to remaining cheese sauce in saucepan, stirring to mix well. Add cooked macaroni, stirring gently to coat. Spread mixture evenly in 33x23-cm pan. Cover and refrigerate at least 4 hours.
Pour 5cm of oil into large deep pan. Heat to 180°C, (350°F) on medium heat. Whisk remaining 3 tbs RedHot Sauce and remaining egg in small bowl. Place panko in separate shallow dish. Scoop cold mac & cheese mixture into about 24 heaped tablespoons and roll into balls. Dip in egg mixture, shaking gently to remove excess. Then roll in panko to coat. Repeat until all mac & cheese balls are coated.
Working in batches, gently place mac & cheese balls in hot oil, being sure not to over-crowd the oil. Cook until crispy and golden brown, about 2 to 3 minutes. Transfer to paper towel-lined plate to drain.
Re-heat reserved cheese sauce in microwave for 1 to 2 minutes, or until heated through, stirring every 30 seconds. Serve Mac & Cheese bites with hot cheese sauce for dipping.