In a small skillet, heat 1 tablespoon of the olive oil over medium heat. Add the celery and onion, and cook until tender, 3 to 4 minutes. Let cool to room temperature.

In a medium bowl, mix the cooled celery mixture with the egg, mustard and ground chicken to combine. Add the bread crumbs, salt and pepper; mix to combine.

Form the mixture into 1-inch balls. Heat the remaining 3 tablespoons olive oil over medium heat. Add the meatballs and cook until golden brown all over, 2 to 3 minutes per side (8 to 10 minutes total). Shake the pan to roll the meatballs around in the hot oil to ensure theyre fully cooked through.

In a medium pot, melt the butter over medium heat. Add the hot sauce and whisk to combine until smooth. Toss the meatballs in the sauce to coat.

Serve the meatballs warm with a side of blue-cheese dressing (if using).

Note: The meatballs can be made up to two days ahead and gently reheated on the stove or in the microwave.