Preheat oven to 350F. Lightly grease two 6-count donut pans. Set aside.
In a large bowl, whisk melted butter, sugar, agave, pumpkin, yogurt, espresso, egg, and vanilla until smooth. Gradually whisk in flour, baking powder, pumpkin pie spice, and salt until batter is smooth.
Fill prepared donut pans 3/4 full of batter and smooth tops. Bake donuts at 350F 15-17 minutes or until donuts test done with a toothpick. Cool donuts 5 minutes in pan, then transfer to a wire cooling rack to cool completely.
Make the glaze: In a small bowl, whisk powdered sugar, espresso, and vanilla until smooth. Dip cooled donuts into glaze and place on cooling rack to set. Once donuts are glazed, serve immediately. Enjoy!