In a large mixing bowl whisk together the plain flour, baking powder, bicarb and salt. Set aside while you melt the butter.

In a small sauce pan over a medium heat melt the butter gently. Remove from the heat and pour into a medium size mixing bowl. Add the sugars to the melted butter and whisk until it’s combined into a thick paste like consistency and all the butter has been absorbed.

Add the eggs one at a time whisking well after each egg. Mix in vanilla and whisk to incorporate. Add the dry flour mixture and switch to a wooden spoon or spatula to mix the flour in.

Stir the chocolate chunks through the dough and let rest in the fridge for 30 minutes. Using an ice cream scoop or your hands, form the dough into balls roughly 3 tablespoons in size. Place them on the tray leaving plenty of space between each cookie. Sprinkle with sea salt if desired and bake for 10-12 minutes or until the cookies are just golden around the edges and have a chewy centre and the chocolate is melted.

Leave the cookies to cool on the tray for about 5 minutes before using a spatula to remove them to a wire rack to cool completely.