Activate the yeast. In the bowl of a stand mixer fitted with whisk attachment, combine 1 (¼ oz) package yeast, 2 tsp sugar, and ½ cup warm water. Mix, then let sit 5 minutes until bubbly.
Add wet ingredients. Add remaining ⅓ cup sugar, 1 egg and 1 egg yolk, ⅓ cup milk, and 2 tsp vanilla extract, then whisk until well combined. Replace whisk attachment with dough kneading attachment.
Add the dry ingredients. In a small bowl, combine 2½ cups flour and ½ tsp Kosher salt. Add to yeast mixture, then knead until dough begins to form a ball. Add 3 Tbsp cubed butter, then continue kneading until dough is smooth and elastic. Transfer dough to a greased bowl, then cover with plastic wrap and let sit until double in size, about 1½ hours.
Cut out the donuts. When dough has doubled in size, press down on it with your hands, then transfer to a lightly floured surface. Roll dough out until it’s about ¼” thick. Use a 2-inch biscuit mold to cut out as many donuts as possible. Transfer to a parchment lined baking sheet. Fold dough scraps together, re-roll out, and continue cutting out doughnuts until all dough has been used. Cover donuts with a dish towel and let rise another 45 minutes – 1 hour.
Fry the donuts. Heat 8 cups of vegetable or canola oil over medium-high heat in a large heavy bottomed pan, about 2-inches deep at least. When oil has reached 365-370 F, begin frying donuts 4 at a time, for about 1 minute per side, or until donut is a deep golden brown. Transfer to a paper towel lined drying rack, then repeat until all donuts are fried.
Make the pistachio cream filling. In the bowl of a stand mixer fitted with beater, mix together 4 oz room temperature cream cheese and ½ cup pistachio cream (or other nut butter) until well incorporated and creamy. Slowly add in ¾ cup confectioner’s sugar a little at a time, then add 1 tsp milk and beat until smooth. Transfer filling to a pastry bag fitted with round piping tip.
Make the peanut butter cream filling. Clean out the bowl, then make peanut butter cream filling: In the bowl of a stand mixer fitted with beater, mix together 4 oz room temperature cream cheese and ½ cup peanut butter until well incorporated and creamy. Slowly add in ¾ cup confectioner’s sugar a little at a time, then add 2 tsp milk and beat until smooth. Transfer filling to a second pastry bag fitted with round piping tip.
Stuff. Use a paring knife to cut a hole in the side of each donut, extending about ⅔ of the way through. Fill half of the fried donuts with pistachio cream, and the remaining donuts with peanut butter cream.
Make the vanilla bean glaze. Combine 1 cup confectioner’s sugar, 1 tsp vanilla bean paste, and 4 Tbsp milk in a medium bowl, then whisk until smooth. Dip one side of each donut in the glaze, then return to wire rack to set. Serve warm!