In a medium to large sized bowl, add in flour, baking soda, and salt. Whisk well to combine.

Place the butter into a medium sized saucepan, set over medium-low heat. Heat, stirring occasionally, until the butter is melted.

In the bowl of your standing mixer add in the butter and both sugars. Beat until smooth and very well combined, about 1-2 mins.

Add the eggs, yolk and vanilla, then add to the batter and beat on high for another 2 minutes, scraping at the edges periodically. Add in the flour mixture and mix on low until combined, scraping at the edges. Ensure it is well combined, but do not over mix. Add in the milk chocolate chunks and toffee bits, and fold until well mixed.

Cover the dough in plastic wrap and refrigerate for an hour .When ready to bake, Pre-heat the oven to 175C (350 F). Line four large baking trays with non-stick parchment paper. Set aside.

Using a large cookie scoop, roll out as many cookie balls out of the dough as possible. Arrange the balls evenly amongst baking trays and bake for 12-13 mins until golden.