• Prepare – Preheat the oven and butter the donut pan.
• Combine Wet Ingredients – In a measuring cup, combine buttermilk and vanilla extract.
• Combine Dry Ingredients – In a bowl, add the flour, salt, baking powder, and lemon zest.
• Beat Butter and Sugar – In a mixing bowl with the paddle attachment, cream together the butter and both sugars until combined
• Add Eggs – Add eggs one at a time and continue to beat.
• Alternate Dry & Wet Ingredients – With the mixer on low, slowly alternate the wet ingredients with the dry until the ingredients are mixed. Scrape down the sides and bottom of the bowl.
• Fold - Using a spatula, gently fold in the blueberries.
• Piping Bag – Add half of the donut batter into a piping bag. If you don’t have a piping bag, the corner of a plastic Ziplock will work. Cut a 2-inch hole at the end and then pipe the batter into the greased donut pan. 
• Bake – In a preheated 350-degree oven, bake the donuts for 15-18 minutes until golden brown.
• Cool - Let the donuts cool for about 10 to 15 minutes before dipping.
• Dip - When the donuts are done cooling, carefully remove them and dip them into the glaze.
• Place them on a wire rack with parchment paper or a baking pan under it to catch the dripping glaze. Dip the top of the donut directly into the glaze and quickly pull up to let it drip. 

Lemon Donut Glaze

• Add the powdered sugar, lemon zest, milk and vanilla extract into a medium bowl. Whisk until smooth.