Cook bacon in a small Sauté pan over medium heat, stirring occasionally until browned and crisp, 8-10 minutes.
Using a slotted spoon transfer bacon to a small bowl.
Add butter pieces to drippings, cook stirring often until butter foams and browns 5-8 minutes.
Strain mixture into a medium sized bowl or bowl of a stand mixer, stir in chopped shallot.
Allow bacon fat/butter mixture to cool 30 minutes or until room temperature.
Add room temperature butter to bacon fat mixture. Using hand mixer or stand mixer beat until light and fluffy. Add chives, vinegar and reserved bacon. Season to taste with salt and pepper.
Place butter mixture in refrigerator and allow to firm slightly.
Butter can be made up to 3 days in advance. Pull 1 hour prior to serving to allow butter to soften.