In a mixing bowl, cream butter until turns a paler yellow.
Add sugar. Beat well. Add extract.
Add 1 whole egg and ONLY egg yolk of second egg. Beat well.
Slowly (1/2 cup at a time) at flour until dough pulls away from the bowl. This tells you it is ready.
Divide dough into two balls. Put in plastic storage bags. Flatten with palms and smooth out to 1/4 inch height. Use back of pan to flatten evenly.
Refrigerate dough for at least one hour or until stiff.
Preheat oven 350F (170C)
Cut open bags carefully. Use cookie cutters to make shapes. Place on baking sheet lined with parchment paper or lightly oiled.
Bake 12 minutes or until lightly golden on edges. Cool before decorating.