In a large bowl, cream the butter and sugar together until pale and fluffy, 2 to 3 minutes.

Beat in the eggs, yogurt, and vanilla until well combined.

In a separate bowl, whisk together the flour, cocoa, baking soda, and salt.

Add the dry mixture to the wet in two or three additions, mixing just until no flour streaks remain. Do not overmix.

Fold in the shredded zucchini by hand.

Grease your pan with cooking spray or line it with parchment. Spread the batter evenly into the pan.

Air fry at 330°F for 30 to 40 minutes, until a toothpick inserted in the center comes out with a few moist crumbs. Begin checking at 30 minutes.

Cool in the pan on a wire rack.

For the frosting, combine the chocolate chips and peanut butter in a small saucepan over low heat, stirring until smooth.

Spread the frosting over the cooled brownies and let set completely, about 1 hour, before slicing into 16 squares.