Preheat your oven to 350°F. Line an 8-inch x 8-inch pan ( for thicker brownies) or a 9x13-inch pan (for thinner brownies) with parchment paper, leaving parchment paper hanging over the edges for handles.
Melt the butter in a large pot over medium heat. Stir in the white sugar, mixing in until the sugar starts to melt into the butter. Remove from the heat.
Mix in the cocoa until thoroughly combined, then beat in the eggs one at a time by hand. (no mixer)
Once everything is combined completely, stir in your flour until just combined with the other ingredients. Do NOT overmix or the brownies will be less chewy.
Scoop/pour the batter out in the prepared pan, smoothing out into an even layer.
Bake for 20-30 minutes, depending on which pan you are using, or until the baked brownies start to pull away from the edge of the parchment paper and the center of the brownies are set. The 9x13 thinner brownies will cook faster.
Sprinkle the chocolate toffee bits on top of the brownies, spreading out evenly. Place back into the oven for 1-2 minutes to make sure they melt, then remove.
Let it cool in the pan completely then remove using the parchment paper handles. Slice into pieces. Store in a close container at room temperature for up to 5 days, or freeze in a freezer-safe container for up to 3 months.