In a saucepan, melt butter over medium heat; stir in flour and cook for 1 minute. Gradually whisk in milk. Cook, whisking gently for about 3 minutes or until starting to bubble and thicken. Reduce heat to low; stir in gouda and cheddar cheeses, salt and pepper. Stir until cheese is melted. Remove from heat and stir in macaroni.
Scrape macaroni mixture into a small, greased baking sheet, cover and refrigerate until completely cold, at least 4 hours or overnight.
Cut macaroni and cheese into 8 equal pieces and gather into mounds. Place flour, eggs and breadcrumbs each in 3 different shallow bowls. Coat each mound in flour and flatten slightly. Coat in egg and let excess drip off. Dredge in breadcrumbs and repeat with remaining mounds.
Preheat waffle iron and spray well with cooking spray. Place 1 or 2 breaded mounds onto waffle iron (depending on size). Close lid and cook for 3 to 5 minutes or until golden and crisp. Carefully remove waffle and place on baking sheet. Repeat with remaining pieces.
In a small bowl, whisk together sour cream and buffalo hot sauce.
Serve waffles with sour cream mixture and sprinkle with chives.
Top 5 Nutrients: Selenium ≥47%DV, Folate ≥30%DV, Vitamin B12 ≥26%DV, Riboflavin ≥25%DV, Thiamin ≥16%DV.