Bakery Style Pistachio Muffins

Preheat your oven to 425°F / 220°C.
Combine the flour, corn starch, baking powder, salt, cinnamon, nutmeg, lemon zest, and finely ground pistachios in a bowl and mix thoroughly, reserving the coarsely chopped pistachios until the end.
Using a stand or hand-mixer, cream the butter and sugar together on medium speed, then add the eggs one at a time and mix on low until fluffy. Add the extracts and food dye if using and then the sour cream, mixing on low until everything is combined.
Starting with the dry mixture, add a little of that and a little bit of milk to the wet ingredients and mix on slow briefly. Alternating the dry mix and milk, continue adding and mixing until you’ve used all of both.
Fold in the reserved pistachios and then scoop the batter into a prepared muffin tin. Use either liners or a non-stick baking spray. Sprinkle tops with coarse sugar if using.
Place muffin tin into the oven and close the door. Immediately turn the heat down to 375°F / 190°C and bake for about 18-20 minutes. Remove from oven when the tops begin to brown, or a toothpick inserted comes out clean. (This is for 6 jumbo muffins, reduce time for 12 standard muffins)