In a large bowl cream together the butter, granulated sugar and brown sugar until fluffy.
Beat in the egg and Irish cream until incorporated.
In a separate medium bowl whisk together the flour, baking soda and salt
Mix the dry ingredients into the bowl with the butter mixture and beat until well mixed. Fold in the chocolate chips.
Drop dough by rounded tablespoonfuls 2 inches apart onto ungreased cookie sheets. Bake in the preheated oven for approximately 8-10 minutes, until they just start to turn golden.