In large saucepan, melt butter over medium heat. Whisk in flour; cook 1 min. Gradually whisk in milk until smooth. Continue whisking while bringing to a boil; simmer 5 min., or until thickened. Whisk in smoked paprika, salt and pepper. Remove from heat and stir in each of the following, mixing in each ingredient before adding the next: 2 cups (500 mL) cheese, chives and egg yolk. Stir in drained cooked pasta; mix well.
Meanwhile, preheat oven to 400°F (200°C). Brush 24 mini-muffin tins with olive oil. Sprinkle bottom of each cup with 1/2 tsp (2 mL) panko.
Fill prepared mini muffin tins with macaroni and cheese mixture. Sprinkle top of each macaroni and cheese bite with remaining panko and cheese. Bake 15 min., or until cheese is golden brown and bubbling. Cool 10 min. before using small spoon to loosen edges around each bite before lifting out of muffin tins. Transfer to serving tray.
Swap smoked Cheddar cheese with aged Cheddar cheese and the smoked paprika for a pinch of cayenne pepper.