I still do not have time to make sugar cookie so I don’t know what recipe is the best . While I search inInternet , I found a few recipe that seems best to me . So I copy and put here for my reference . Hope the authors don’t mind because I already link back .

Step 1. In mixer, cream butter and sugar until fluffy.
Step 2. Mix in egg and vanilla.
Step 3. Add flour cup-by-cup.
Step 4. Split dough into 2 parts. Form each into a brick. Sandwich each brick between two sheets of wax paper, then roll each brick into a sheet using 1/4 inch cookie slats. Refrigerate dough sheets for 20 minutes before cutting shapes. Save dough scraps to make a third sheet of cookies.
Step 5. Bake cookies for about 14 minutes at 350 degrees F. Cookies are done when they start to turn golden on the edges. Transfer cookies to racks to cool.
Glace Icing
4 cups powdered sugar
6 tbs milk
6 tbs light corn syrup
1 tsp clear vanilla extract
Step 1. Mix sugar and milk with whisk or fork until smooth. Mix in corn syrup and vanilla. Icing should be thin, forming a drizzle. This consistency is the flood icing, the background for the cookies. Split icing into several bowls – one for each color. Dye icing to the desired colors. (I left one bowl white and used Wilton Royal Blue for the other two, one with more food coloring than the other.)
Transfer half the icing from each bowl to squeeze bottles to flood the cookies. (Make sure to leave enough in the bowls for the piping icing.) To make the background of the cookies, make a pool of icing in the center of the cookie, then use the back of a spoon to spread the icing towards the edges.
Step 2. Half the icing is left in each of the bowls. This will become the piping icing. Mix powdered sugar into each bowl until icing is the consistency of toothpaste. Transfer icing to piping bags and decorate. (I used Wilton #2 tips.)
Each of the three cookie shapes here have a different design – plaid for the parallelograms, sugar pearls and stripes for the small circles, and flowers for the large circles. For most of the piping here, I waited until the flood had nearly dried before piping the second layer.
The large circle flower design was done by piping wet-on-wet. When the flood/background is just starting to get tacky, pipe dots into the wet icing. Use a thinner piping icing if necessary. (Icing can always be thinned with milk or thickened with powdered sugar.)
 This icing will get hard if you let the cookies dry overnight, but it won’t become as dry as royal icing.