Preheat the oven to 350F and line a 9x5 loaf pan with parchment paper, leaving the sides high for easier removal, and spray exposed ends with a cooking spray.
In a medium bowl, whisk together cocoa powder, all-purpose flour, sea salt, baking soda and baking powder.
With a stand mixer, cream together the sugar and butter together for about 5 minutes.
Add in the vanilla and 1 egg and beat again until combined.
Add in ½ the dry ingredients, 1 egg and ⅓ cup milk, and beat again.
Repeat this step once more with the remaining ingredients and mix until combined.
Add chocolate chips and toffee bits, if desired. Stir until blended.
Pour mixture into the prepared loaf pan and bake for about 50 minutes or until a toothpick inserted into the middle of the loaf comes out with moist crumbs.
Place on a rack and cool in the pan for about 10 minutes then remove it and allow it to fully cool before making your frosting.