Infuse sugar with zest: add the sugar and zest to the stand mixer bowl and rub the sugar and zest between your fingertips to create a lemon sugar. This helps release the natural oils and infuse more lemon flavor into the cookies.
1 1/4 cup granulated sugar, 1 Tbsp. lemon zest (or more for more lemony flavor)
Cream: add the butter and cream the butter and sugar for 2-3 minutes, scraping down the sides of the mixing bowl as needed.
3/4 cup unsalted butter, softened
Dry ingredients: meanwhile, whisk together the flour, cornstarch, baking powder, baking soda, and salt. Set aside.
3 cups all-purpose flour, spooned and leveled, 1 tsp. cornstarch, 1/2 tsp. baking powder, 1/2 tsp. baking soda, 1/2 tsp. salt
Add wet ingredients: Add the egg, sour cream, extracts, and lemon juice. Mix again until combined, once again scraping down the sides of the bowl as necessary.
1 large egg, room temperature, 1/2 cup sour cream, room temperature, 1 Tbsp. lemon juice, freshly squeezed, 1 tsp. lemon extract, 1 tsp. vanilla extract
Add dry ingredients: gradually spoon in the dry ingredients and mix just until incorporated.
Add white chocolate: turn the mixer off, and stir in the white chocolate chips with a rubber spatula.
1 cup white chocolate chips, plus more for garnishing the tops
Chill: chill the cookie dough for at least 1 hour. It’s pretty sticky from the sour cream so this chill time will help not only develop flavors but make it easier to handle.
Preheat and prep: preheat the oven to 350°F and line 2 baking sheets with parchment paper.
Roll in granulated sugar: scoop the chilled cookie dough with a 2 tbsp. Scoop and roll in granulated sugar. If the dough is still a little sticky, the granulated sugar makes it a little easier to work with and roll in a ball. Place on the prepared cookie sheet and press down slightly to flatten them.
Bake: Bake for ~8-10 minutes (under-baking is key!) if you over-bake these ones they can get dry. I take them out right before the edges turn golden because I noticed if they got too golden they were dry.
Lemon Glaze: whisk together the lemon glaze in a small dish and gently brush the glaze on top once the cookies come out of the oven. This lemon glaze locks in flavor and keeps these cookies super moist! Press a few more white chocolate chips on top and garnish with lemon zest, if desired.
1/4 cup granulated sugar, 2 Tbsp. lemon juice
Cool: cool on the cookie sheet for a few minutes, then transfer to a parchment paper lined wire rack. ENJOY!!! :) They stay soft and yummy for days!