In large bowl, using electric mixer or stand mixer on medium speed, beat butter and two sugars. Add egg and vanilla; beat until fluffy.
Measure flour, baking soda, and salt in a bowl and mix together. Gradually beat into butter mixture on low speed or by hand until just mixed. Stir in chocolate chips and cranberries.
Drop by rounded teaspoonfuls, two inches apart on ungreased cookie sheets. Bake 10 to 12 minutes, or until edges start to brown. Let rest about a minute, and then lift them to parchment paper and cool completely.