In a medium mixing bowl, combine the flour, baking powder, baking soda, cinnamon and salt, set aside. Line baking sheets with parchment paper or Silpat liners.
In a large mixing bowl, combine the butter and sugars. Whisk to combine. Add in the eggs, one at a time, and the vanilla.
Add in the dry ingredients. Mix until fully combined, careful not to overmix. Mix in the oats, mini chocolate chips, and crushed Cadbury eggs*.
Cover and allow the dough to chill for 30 minutes. Preheat oven to 350 degrees F.
Using a measuring spoon or portion scoop, scoop even sized balls of cookie dough – roughly 1 oz. per cookie. Arrange evenly on the prepared cookie sheet, leaving about 2 inches between each cookie.
Bake at 350 for 9-11 minutes, cookies will still be soft. Allow to cool for a few minutes on the cookie sheet before transferring to a cooling rack.
Notes
**Crush the Cadbury eggs by using the side of a knife and gently pressing down, this is easier than trying the cut through them! Or crush them in a food processor.