3/4 cup unsalted butter, softened
1 1/4 cups sugar
1 Tablespoon finely grated citrus zest (Meyer or regular lemon, tangerine or lime)
2 large egg yolks, at room temperature
3/4 teaspoon lemon extract (or use all orange extract for tangerine cookies)
1/4 teaspoon orange extract
2 cups all-purpose flour
1/4 teaspoon baking soda
1/4 teaspoon fine salt
1 cup powdered sugar, sifted
2 Tablespoons colored sanding sugar (yellow, orange or green, depending on the flavor of the cookie)
1 Tablespoon finely grated citrus zest (the same flavor of the cookie)
2 to 3 Tablespoons freshly squeezed citrus juice (the same flavor of the cookie)
Evenly space the oven racks in the oven and preheat to 375ºF on the convection setting, if available.
Line 2 baking sheets with parchment paper or silicone mats.
Beat the butter in a medium bowl with an electric mixer on medium-high heat until smooth.
Add the sugar and citrus zest and continue to beat until light and fluffy, about 2 minutes.
(The creaming is important to get a great texture so don't skimp here.)
Add the yolks, 1 at a time, beating well after each addition.
Beat in the extracts.
Whisk the flour, baking soda and salt together in a bowl.
Stir the dry ingredients into the wet mixture, mixing at low speed to make a soft dough.
Scoop the dough into rounded heaping tablespoons with a cookie scoop or measuring spoon.
Space the cookies about 2-inches apart on the prepared pans.
Freeze for at least 30 minutes.
(The cookies can be frozen for up to 1 month.)
Bake the cookies, straight from the freezer, until edges are firm and bottoms are lightly browned, 15 to 17 minutes.
Transfer to a rack to cool.
Mix the powdered sugar, colored sugar and appropriate flavored zest in a medium bowl.
Add the citrus juice and mix with an electric mixer to make a firm but pourable icing.
(If needed, add up to 1 teaspoon more juice, but keep in mind that if the icing is too loose it won't set.)
Dip the rounded side of the cooled cookies into the icing; then let the excess icing fall back into the bowl.
Dry cookies icing side up on a rack.