Line a large baking sheet with parchment paper; set aside.
In a medium-sized bowl combine flour, baking powder, and salt; set aside.
In the bowl of your mixer fitted with the paddle attachment, cream together sugar, lemon zest, and butter until well combined; about 2 minutes. Add in egg and beat until combined. Add yogurt and vanilla; beat until combined.
Slowly add the dry ingredients into the wet ingredients, and mix until just combined. Gently fold in blueberries. The dough will be very thick at this point. That's a good thing!
Using a 1/4 cup sized measuring utensil (or just eyeballing it), form large (about a 1/4 cup) balls of dough, and place them on the prepared baking sheet, leaving 2 inches in between for spreading.
Place the pan in the refrigerator for one hour, and up to 4.
Preheat your oven to 375 degrees (F) 30 minutes prior to baking.
When ready to bake, place pan in the oven and bake for 13-15 minutes, or until the centers are set and the edges are just becoming golden - be sure not to over bake!
Let cookies cool on the sheet pan for 5 minutes before transferring to a cooling wrack to cool completely.
While they cool, you can make the glaze!
Simple mix the lemon juice with the sugar, stir, then drizzle over cooled cookies.
*Cookies will keep for up to two days when stored in an airtight container.
*Yields approximately 12 muffin top cookies, depending on how you shape them.