Sift the Flour into a large bowl, add the salt, baking powder, and baking soda, and set aside.
In the mixing bowl of a stand mixer, combine the wet ingredients. Add the unsalted butter, lemon juice, tablespoon of lemon zest, sugar, vanilla and eggs, and mix until creamy and smooth.
Add the flour mixture a little at a time, alternating with the milk until all ingredients have been added. Scrape down the sides of the mixing bowl, and blend on high speed for about 1 minute.
Add the blue food coloring gel, and mix on medium speed to blend. Remove the mixing bowl from the stand, and gently fold in the blueberries.
Place cupcake liners in a 24 count, or 2 12 count muffin tins. Fill the cupcake liners about 2/3 full with the cake batter. Bake at 350 degrees for about 20 - 22 minutes, or until a toothpick inserted in the center comes out clean Remove from oven to a wire rack to cool. After about 10 minutes, remove the cupcakes from the muffin tins, and continue to cool on wire racks.
While the oven is still hot, cut up 8 -10 of the frozen french toast sticks into small squares with kitchen scissors (see photo), place parchment paper on a cookie sheet, and place the cut up pieces of french toast sticks on the parchment paper.
Combine the sugar and cinnamon, and sprinkle over the french toast pieces. Place in the oven for about 15 - 20 minutes, or until they are golden brown. Remove from oven and set aside to cool.
Greek Yogurt frosting recipe from Chocolate Covered Katie. Blend all ingredients (cream cheese, Greek yogurt, stevia, vanilla, and natural blue food coloring) using a stand or hand mixer until smooth. Add natural blue food coloring.
Transfer to a frosting piping bag.
Pipe the frosting on the top of the cupcakes leaving a hole in the middle. Gently press a few blueberries into the frosting.
Fill the hole with the French toast cubes. Enjoy!