Preheat oven to 350º and line a baking sheet with parchment paper. In a medium saucepan melt butter and bring to a boil, stirring constantly, until butter passes from foamy to light amber and smells nutty (do not scorch). Immediately remove from pan, pouring butter into a mixing bowl, stirring to quickly stop cooking. Set aside. Combine flour, baking soda and sea salt and set aside. Add to the browned butter: sugars, eggs and vanilla, stirring to combine, then pour into flour mixture and stir with a spatula or spoon. Add chocolate and toffee. Drop onto baking sheet in 2 T portions, 2” apart, arranging a few chocolate chips on top. Bake 10-12 min until edges are golden. Sprinkle with scant pinch of flake salt, as desired. Cool on sheet for few minutes before transferring to rack to cool.