Cookie:
1 c. Butter, softened
1/2 c. Powdered Sugar
2 c. Flour
1 tsp. Grated Orange Zest
1 tsp. Grated Lemon Zest
1/4 tsp. Salt
Granulated Sugar, for coating

In mixing bowl cream butter and powdered sugar.
Beat until light and fluffy.
Gradually add flour, citrus zest and salt.
Combine until soft dough forms.
Cover and chill 2 hours.
Roll dough into 1″ balls.
Place on parchment lined cookie sheets.
Flatten each cookie with bottom of a glass dipped in granulated sugar.
Prick top of each cookie with tines of a fork.
Bake 10-12 minutes at 400°F.
Spread 1/2 tsp. filling on bottom side of half of cookies.
Press bottoms of remaining cookies against filling to form sandwiches.

Filling:
2 c. Powdered Sugar
1/4 c. Butter, softened
1/4 tsp. Lemon Extract
2-3 tsp. Milk

Cream together powdered sugar, butter, extract and milk.
Beat until creamy.
Add more milk if necessary.