Preheat oven to 375°F. Have ready two parchment lined baking sheets.
Mix the flour, baking powder, baking soda and salt together in a bowl and set aside.
In the bowl of a stand mixer fitted with a paddle attachment or in a large mixing bowl using a hand-held electric mixer, beat the butter until creamy. Beat in the Coffee Mate, brown sugar and granulated sugar and continue beating for another 2-3 minutes or until very light. Reduce mixer speed and beat in the egg. When egg is mixed, beat in the vanilla. Add half of the flour mixture and stir until incorporated. Add remaining flour mixture, followed by the oats and toffee.
Using a tablespoon, scoop up balls of dough and arrange on a parchment lined baking sheet spacing about 2 ½ inches apart. Bake for 10 to 12 minutes or till edges are golden. Transfer to a wire rack and cool completely before serving.