Combine flour, baking soda, salt, and baking powder in a medium bowl; set aside.
In the bowl of your stand mixer, or a large mixing bowl, add butter and sugar and mix for about 2 minutes. Add the eggs, one at a time. Then add the vanilla and mix well.
Slowly add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Stir in the oats, candies, and chocolate chips with a wooden spoon.
**Refrigerate for at least one hour.**
Preheat your oven to 350 degrees.
Line two baking sheets with parchment paper. Using a cookie/ice cream scoop, place 12 mounds of cookie dough on your baking sheet (or if they're larger sheets like mine, you can do 15 mounds), flattening them out a bit as you go. Bake for 10 to 12 minutes, or until they are slightly brown around the edges, but still a bit soft in the middle.
Place on a cooling rack to cool completely.