I believe Georgia said these were called "Modern" sugar cookies because of their use of oil instead of all-butter or shortening. But I suspect "Modern" might also refer to the streamlined method which doesn't involve the tedious rolling and cutting of a traditional sugar cookie. This method is quicker, and it's easy for kids of various ages to participate.
1 cup white sugar, plus more for pressing
1 cup confectioner's sugar
1 cup butter, softened
1 cup oil
4 cups all-purpose flour
1 teaspoon baking soda
1/2 teaspoon cream of tartar
2 teaspoons vanilla
1/4 teaspoon salt
1/4 cup white sugar
2 tablespoons colored sugar sprinkles
Preheat oven to 325 degrees F
Cream together sugars and butter.
Beat in oil, eggs and vanilla. Add flour, baking soda, cream of tartar and salt.
Chill dough for 12 hours. Roll into walnut size balls, place on an ungreased cookie sheet.
Mix the two pressing sugars in a shallow dish.
Grease bottom of a glass or measuring cup, then dip into sugars and press cookie flat. Repeat for each cookie.
Bake for 10 minutes or until edges start to turn golden.