Beat butter and sugar in standing mixer until light and fluffy, about 3 minutes on medium high speed. Add lemon zest and eggs, one at a time, beating until incorporated. Stir in lemon extract, if using.
In separate bowl, mix flour, cornmeal, rosemary, baking powder and salt.
Add dry mixture to butter mixture on low speed in 2 parts, just until dough comes together. Stir in pine nuts. Cover the and refrigerate for 1-2 hours, until dough is firm and scoopable.
Heat the oven to 325°F and line 2 large baking sheets with parchment paper.
Scoop dough into tablespoon-sized balls (I like to use a cookie scoop) and arrange on cookie sheets.
Bake 12 minutes, or until the cookies are puffed and slightly golden on edges. Cool cookies on baking sheet 5 minutes before transferring to a rack to cool completely.
To make glaze, stir together powdered sugar, cream and lemon juice until smooth. Spread some glaze on each cookie; top with a few rosemary sprigs and a pine nut.