Preheat your oven to 375 degrees and line sheet pans with parchment paper.
To a large bowl sift together flour, baking soda, baking powder and fine sea salt. Set aside.
To a separate bowl or stand mixer, beat softened butter with sugar and brown sugar until fluffy.
Add eggs, one at a time. Add vanilla. Blend until everything is incorporated.
Slowly add the dry ingredients into the wet. Blend until incorporated.
Pour toffee bits in the dough and fold in by hand.
Use a standard ice cream scoop to scoop dough out. Scrape along the top of the rim of the bowl to create the flat bottom of the cookie.
Bake 5 cookies at a time on a parchment lined sheet pan for 9-10 minutes. Remove from the oven and immediately top with flaky salt.
Only bake one batch at a time in the middle rack.
Allow to cool for at least 15 minutes on the hot sheet pan before placing elsewhere to fully cool. Tastes the best 8+ hours after coming out of the oven.