Preheat the oven to 200C/400F and line two large cookie sheets with nonstick baking paper.
Using a stand mixer with the paddle (and scraper) attachment, beat the sugar and butter until light and fluffy. About 4 minutes. Scrape the bowl a few times if necessary.
Add the egg, vanilla, baking powder, bicarb and salt and continue to beat until well incorporates.
Add the flour to the bowl in one go and mix briefly until combined. Do not over mix here.
Add all the chocolate (or chocolate chips) and mix briefly until well incorporated. It will still be a bit crumbly, but you shouldn’t see any flour and the chocolate will be well distributed in the dough.
Scrape down the bowl with a spatula and incorporate in the dough.
Weigh out approximately 85-90gms of dough in a loose ball, and roughly roll with your hands. You don’t need to compact the dough too much.
Place 5 cookie balls on a tray spaced out. Flatten them down a bit to increase the surface area and press additional few halved mini eggs with the domes facing up into the surface