Preheat oven to 350°F.
Finely zest two lemons using a microplane.
In a large bowl, mix together flour, baking soda, and salt.
In a separate large bowl, add 1 cup of frozen blueberries.
Either in the microwave or on the stovetop, thaw the frozen blueberries until they're soft and jammy. (In the microwave this should take about 30 seconds over high heat, and on the stovetop it should take about 2-3 minutes on medium heat.)
Let the blueberries cool for about 2-3 minutes.
Add coconut sugar, honey, egg, vanilla, coconut oil, and lemon juice to the thawed blueberry mixture.
Mix at a high speed. You want to "mash" the blueberries into the mixture, making it so that they are puréed and fully combined with the other ingredients. The mixture should be a deep purple color.
Add dry ingredients to wet ingredients and mix until well combined.
Line a large baking sheet with parchment paper.
Scoop out 2-Tablespoons worth of batter and place onto the baking sheet. Repeat with remaining cookie dough, making sure they are all at least 2-inches apart.
Place 2-3 additional blueberries on the surface of the cookie dough balls.
Bake cookies in a preheated oven for 13-15 minutes, or until the edges are slightly golden.
While the cookies are baking, whisk together the lemon glaze ingredients in a small bowl (powdered sugar, non-dairy milk, and lemon zest).
Once cookies have cooled to room temperature, drizzle lemon glaze over each one.