Mix the flour, baking soda and salt in a bowl and set aside.

Beat the butter and sugars together till fluffy and creamy. This takes me about 5 minutes.

Add the egg, beat for a minute.

In goes the vanilla, beat till combined.

Add the dry ingredients and mix till just combined.

Fold in M&Ms with a spatula.

Let the dough rest covered in the fridge for a few hours or overnight.

Preheat the oven to 350 degrees & line a baking sheet with parchment paper

Mix the salt and sugar for topping in a bowl

Make 1-inch balls of dough with a spoon or cookie scoop and drop into the bowl, roll it gently to coat and place on the baking sheet.

Repeat till your sheet is full taking care to leave 2 inches between the cookies.

Bake for 10-13 minutes or until the edges are golden brown but the cookie is still very soft in the middle. The cookie will still be fragile.

Wait a few minutes and then carefully transfer the cookies to a cooling rack to cool all the way through.