Pre-heat oven to 400 degrees.
Cut off top head of garlic to expose cloves just a little bit. Place garlic cut-side-up in the cavity of a muffin tin and rub olive oil over the exposed cloves. Wrap foil over the garlic.
Roast garlic for 30-35 minutes, until cloves are soft and golden. Remove from oven and let cool enough to handle. Once cooled, remove each clove of garlic by gently squeezing. Place in bowl and set aside.
Lower oven temperature to 375 degrees and spray a 12-cavity muffin tin lightly with cooking spray.
Boil elbow macaroni in a pot of lightly salted boiling water, about 2 minutes less than package recommends for al dente (the macaroni will finish cooking in the oven). Drain and set aside.
While macaroni is cooking, melt 2 Tbsp butter in a large saucepan over medium high heat. Whisk flour into butter until smooth, about 1 minute. Add salt and pepper.
While continuing to whisk, slowly pour milk into mixture. Stir for about 3 minutes as mixture thickens and comes to a simmer. Don't let mixture come to a full boil.
Lower heat to medium-low and stir in roasted garlic cloves and Parmigiano Reggiano cheese, until sauce is smooth.
Add macaroni to pot and stir to full coat pasta with sauce.
Melt remaining 1 Tbsp butter in a small bowl and stir in panko.
Evenly divide macaroni mixture among cavities in prepared muffin tin. Sprinkle panko mixture over the top and top with chopped parsley.
Bake for 15 minutes, until panko is golden. Let mac and cheese cups cool for about 5 minutes before removing from muffin tin and serving.