In a large mixing bowl or stand mixer, combine butter, sugars, vanilla until light and fluffy (about 3 minutes). Blend in egg until just combined.
In a medium mixing bowl, whisk together flour, baking powder, baking soda, and salt. Gradually incorporate into wet mixture.
Fold in toffee bits.
Cover dough and refrigerate 2+ hours.
Preheat oven to 350°F. Line cookie sheets with parchment paper.
Make 1" dough balls and drop onto cookie sheet spread 3" apart.
Top with sea salt and bake 8 minutes or until edges are just golden brown.
Allow cookies to cool on baking sheet for 1 minute. Transfer from cookie sheet to wire baking rack to finish cooling.
