Preheat oven to 350F. Line a 9-in square baking pan with parchment paper and set aside.

In a large bowl, beat peanut butter, yogurt, egg, vanilla, and sugar until creamy and smooth. Add oats, chia seeds, flour, baking soda, cinnamon, and salt, gently stirring until a thick dough forms (dough will be slightly sticky.

Spread dough evenly into prepared pan. Bake bars at 350F 20 minutes or until edges just begin to turn golden. Cool bars completely on a wire cooling rack.

Make the glaze: In a small bowl, whisk glaze ingredients until a thick glaze forms, adding more milk if necessary. Drizzle glaze evenly over cooled bars and let set 10 minutes before lifting parchment paper-lined bars out of pan and slicing into squares. Enjoy!