Preheat oven to 350 degrees Fahrenheit. Line a large baking sheet with parchment paper or a baking mat.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In the bowl of a standing mixer with the paddle attachment, beat together the room temperature butter and both sugars until fluffy. Add the eggs and vanilla extract and beat until smooth, scraping down the sides as needed.

Add the dry ingredients to the butter mixture and mix on low speed until just combined, being careful not to overmix.

Stir in the toffee bits (and chocolate chips if using) with a spatula or wooden spoon.

Using a cookie scoop or rounded scoop (about 2 tablespoons), place the balls of dough on to the prepared baking sheet, leaving at least 2 inches for the cookies to spread. I only place 8 dough balls on the sheet at a time.

Press about a tablespoon, or a generous pinch or two, of the chopped Milk Chocolate Heath Bars into the top of each dough ball. Bake for 10 to 12 minutes or until the edges are just beginning to turn golden and the centers are still soft. Remove from oven and let sit on the baking sheet for at least 5 minutes before removing. Sprinkle with sea salt flakes if desired.