To make the donuts: In the bowl of a stand mixer combine all the dry ingredients and mix to combine. In a small bowl whisk together the vanilla, eggs and sour cream. Pour the wet into the dry and mix on low with the paddle attachment. Pour in the melted butter and mix until a soft cookie dough forms, then cover and refrigerate for 30 minutes.

On a well floured surface, roll the dough out to about 3/4" thick. Using a floured 3 1/2" circle cutter, cut as many circles from the dough as possible and place them on a parchment lined baking sheet. Gather the scraps of dough up, and bring them back together and repeat until all the dough has been used up. Using a 1" circle cutter, cut holes from the middle of each donut and place them on the tray. Refrigerate donuts for 15 minutes.

Heat 2 inches of canola oil in a high sided pot to 350 degrees F. Using a 2" circle cutter, gently press the cutter into the donut around the middle ring just to score the top, but don't press all the way through (just enough to leave a small imprint). Gently lower 2-3 donuts into the oil, scored side down, and fry for 1-2 minutes per side until golden brown. Transfer to a wire rack set over a baking sheet. Once all the donuts have been fried, fry the donut holes for 2 minutes, until golden brown and then transfer to the wire rack.

To make the glaze: In a small saucepan, melt the butter over medium heat. Cook until slightly golden brown, and then remove from heat and allow to cool slightly. Whisk all the remaining ingredients together in a mixing bowl until smooth. While the donuts are still warm, dip them into the glaze and return them to the wire rack. Then, coat the donut holes in the glaze and allow them to dry. Serve still slightly warm.