Preheat & Prep – Set your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Dry Mix Magic – In a bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
Creamy Bliss – Beat butter and sugar until light and fluffy (about 3-4 minutes).
Egg & Vanilla Swirl – Add egg and vanilla extract, mixing until smooth.
Bring It Together – Slowly mix the dry ingredients into the wet ingredients until just combined.
Berry Burst – Gently fold in blueberries and lemon zest. If using, mix in purple food coloring.
Shape & Sprinkle – Scoop dough into 1-inch balls, place on the baking sheet, and sprinkle coarse sugar on top.
Bake to Perfection – Bake for 12-15 minutes until edges are golden but centers remain soft.
Cool & Indulge – Let cookies cool for 5 minutes on the baking sheet before transferring to a wire rack. Enjoy!