• Preheat the oven to 350 degrees Fahrenheit and line a regular size cupcake pan with cupcake liners. Set aside.

Make the Blueberry Syrup

• Place the 1 cup blueberries, ½ cup granulated sugar and 1 pinch kosher salt together in a saucepan set over medium heat.
• Cook (stirring frequently and smashing the blueberries with the back of a spoon) for about 5 min until it begins to boil.

  Once boiling turn the heat to low and let it simmer for an additional 5 minutes, stirring frequently.
• Using an immersion blender or a regular blender, carefully blend the hot blueberries until there are no chunks.
• Then place a mesh colander over a heat proof bowl and pour the mixture through the colander to strain it. Gently press down on the blueberry chunks with the back of a spoon to get all the liquid out.

  Set aside to cool while you make the cupcakes.

Make the Blueberry Cupcakes

• In a large bowl, whisk together the 1 ¼ cups gluten free flour and 2 tablespoons of cornstarch.

  Once combined, whisk in the 1 ½ teaspoons baking powder, ½ teaspoon baking soda and ¼ teaspoon kosher salt. Set aside.
• In a small bowl, using a spoon, mix together the 4 rounded tablespoons of cornstarch (52 grams) with 6 tablespoons of water until thin and watery. It will be thick and tacky at first.
• In a large bowl of an electric mixer fitted with the paddle attachment, beat the ½ cup unsalted butter or vegan baking stick and the 1 cup granulated sugar until it is soft and creamy. About 2-3 minutes.
• Slowly beat the cornstarch water mixture into the creamed butter and sugar. 

  With the mixer still on low speed, mix in the ½ cup sour cream, 2 teaspoons pure vanilla extract and 2 tablespoons vegetable oil. The mixture will look chunky. That's normal.
• Slowly mix in the gluten free flour mixture a little at a time until all combined.
• Slowly pour the ½ cup plus 2 tablespoons milk into the batter while the mixture is on low speed. Mix until just combined.

  Once it is combined, turn off the mixer and use a spatula to scrape the sides of the bowl. You don’t want to over mix this. Just make sure everything is fully combined. The batter will be thin. Set aside.
• Take the 1 cup of blueberries and gently toss them in ½ tablespoon of gluten free flour.

  Then using a spatula, gently and carefully fold them into the batter. Try not to break the blueberries apart or your cupcakes will turn blue/green.
• Use an ice cream scoop to fill the cupcake tins ¾ way to the top. Smooth the tops with a small knife. There should be enough batter for 16 cupcakes.

  You do not want to overfill the cupcakes. This will result in them spill out of the top and not baking evenly inside.
• Bake the cupcakes at 350 degrees Fahrenheit for 24 minutes or until the tops of the cupcakes are golden brown, spring back at you when carefully touched or when a toothpick inserted comes out clean.

  Let the cupcakes cool almost completely in the pan before trying to remove them.

Make the Blueberry Frosting

• While the cupcakes are baking, make the frosting.

  In the large bowl of an electric mixer or using a hand held mixer, beat the ½ cup unsalted butter or vegan baking stick until smooth and creamy. About 2 minutes.
• With the mixer on very low speed, slowly add in the 4 cups confectioners' sugar and 5 tablespoons blueberry syrup. Beat until combined.
• While the mixer is on, slowly add in the 4 teaspoons water a little at a time until you get the desired consistency. You may not need to use all the water. You want the frosting to be soft enough to pipe yet still be able to hold its shape.

Assemble the Cupcakes

• If you have piping bags, pipe the blueberry frosting on top of each cool cupcake.

  If you don’t have piping bags, put a thin layer of frosting on top of each cupcake.

  If you frosted the cupcakes by hand, pop the cupcakes in the fridge for 15 minutes to let that thin layer harden. 
• If desired, drizzle the extra blueberry syrup on top of the blueberry buttercream frosting. Top with a fresh blueberry or eat as is! Enjoy!