Heat the oven at 180o/350°F. Grease the large cookie sheet with shortening or cooking spray.
In a large bowl, beat sugar and butter with an electric mixer on medium speed, or mix with a spoon. Now beat in vanilla and eggs until smooth.
Stir in flour, baking powder and salt to the mixture and add chocolate chips. Divide dough in half. On the cookie sheet, shape each half into 10x3-inch rectangle with greased hands.
Bake for about 25 minutes until the toothpick comes out clean. Let them cool for 15 minutes then move to the cutting board. Using a sharp knife cut crosswise into 1/2-inch slices.
Place slices on the cookie sheet and cut sides down. Bake for 10-12 minutes until golden brown and dry on top.
Turn the cookies and bake for about 10 minutes until golden brown. Remove from cookie sheets to cooling rack.