• Preheat the oven to 425 degrees.  *Note that you will be turning the oven down to 350 degrees after the first 8-10 minutes of baking.  Baking at a higher heat to start will allow them to rise more.  Place 12 paper liners in muffin tins.
• Cream butter and sugar together in a large bowl using a hand mixer.  Add eggs and mix until combined well and creamy, then add buttermilk and lemon juice.  Mix again until combined well.  It may look a little curdled or like it is separating some.  That is okay.
• Add in the flours, baking powder, baking soda and salt.  Using your hand mixer, combine them completely, scraping down the sides as needed. 
• Using a small scoop or tablespoon, place a scoop of batter (without blueberries in it) into each cupcake liner. 
• Now combine the remaining batter with the blueberries, stirring gently with a wooden spoon or spatula.  Spoon the blueberry mixture evenly into each muffin liner, filling only ⅔ of the way.
• Place in the 425 degree preheated oven for approximately 8-10 minutes, when you notice that they have started to rise nicely, turn the oven down to 350 and continue baking for 8-10 more minutes until lightly browned and set in the center. 
• Remove from the oven and let cool before drizzling with glaze.

For the Glaze:

• In a small bowl combine a small amount of lemon juice (or milk substitute) on top of the powdered sugar and stir.  Add a little more at a time until the sugar dissolves.  Use your spoon to press out any lumps against the side of the bowl.  Once a thick, creamy looking mixture develops, the glaze is ready.