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.
1 cup unsalted butter, ½ cup white granulated sugar, ½ cup light brown sugar, 1 teaspoon vanilla extract, 1 egg
In a medium mixing bowl, whisk together flour, baking powder, baking soda, and salt. Gradually incorporate into wet mixture.
2½ cups all purpose flour, ½ teaspoon baking powder, ½ teaspoon baking soda, ¼ teaspoon salt
Fold in toffee bits.
1 cup 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.
sea salt
Allow cookies to cool on baking sheet for 1 minute. Transfer from cookie sheet to wire baking rack to finish cooling.
Notes
Tips
Use softened butter for best results.
Use a cookie dough scoop for uniform cookies. Making cookies consistent in size ensures some cookies don't over bake while others remain under baked.
Refrigerate dough to prevent spreading.
Transfer cookies to cool to prevent over baking.
To Store
Refrigerator - In their airtight container or bag, store in the refrigerator.
Freezer - It's actually better to store cookies in the freezer over the refrigerator. If you're planning on freezing them, wait for them to cool, and then put the cookies into an airtight container or bag, with parchment paper between layers, and freeze up to three months.