Ingredients:

  • 320g all-purpose flour
  • 1 tsp cornstarch
  • 1 tsp baking soda
  • 0.5 tsp fine sea salt
  • 225g unsalted butter, softened
  • 200g packed light brown sugar
  • 100g granulated white sugar
  • 1 large egg
  • 1 large egg yolk
  • 2 tsp pure vanilla extract
  • 250g milk chocolate M&Ms
  • 90g semi-sweet chocolate chips

Instructions:

  1. Whisk the 320g flour, 1 tsp cornstarch, 1 tsp baking soda, and 0.5 tsp sea salt in a medium bowl. Note: This ensures the leavener is evenly distributed.
  2. Cream the 225g softened butter with 200g brown sugar and 100g white sugar until pale and fluffy.
  3. Beat in the whole egg, the extra yolk, and the 2 tsp vanilla extract. Note: Scrape the bowl to ensure no butter streaks remain.
  4. Fold the dry ingredients into the wet mixture slowly. Stop as soon as the last streak of flour disappears.
  5. Stir in the 250g M&Ms and 90g chocolate chips by hand.
  6. Scoop the dough into rounded balls (about 2 tablespoons each) onto a parchment lined tray.
  7. Chill the dough balls in the fridge for at least 15 minutes. Note: This prevents excessive spreading.
  8. Bake at 350°F (175°C) for 10 minutes until the edges are set and just barely tan.
  9. Press a few extra M&Ms into the tops of the warm cookies immediately after removing from the oven.
  10. Cool on the baking sheet for 5 minutes before moving to a wire rack to finish.