Preheat oven to 350 degrees F.

In a large mixing bowl, combine cold cubed butter and brown sugar until well combined. This takes slightly longer than with room temperature butter. Once fluffy, add in your peanut butter, vanilla and eggs, mixing until well combined.

In a separate bowl, combine flour, cornstarch, salt, baking soda and baking powder. Combine these ingredients with your wet ingredients, as well as white chocolate chips and candies, stirring until just combined. This is a fairly dry dough.

Scoop or drop cookies by spoonfuls onto cookie sheets. Because this is a fairly firm cookie dough, they will will not spread out a great deal, and instead somewhat hold their shape while baking.

Bake for approximately 9-12 minutes or until edges start to turn slightly brown. Remove from oven and let cool on cookie sheets for approximately five minutes, then transfer to wire racks to finish cooling. Store in an airtight container.

Makes approximately 4 dozen cookies, about 1 1/2" in diameter.