In a medium mixing bowl, whisk together flour, baking powder, soda and salt; set aside. In an electric mixer, beat butter with sugars until light and fluffy. Add egg, yolk and vanilla; beat just until well combined. Add flour mixture; beat on low speed just until flour is no longer visible. Fold in candy, oats, pretzels and chocolate chips by hand. Form 24 evenly sized rounded spoonfuls (or use a #40 cookie scoop); drop 2" apart on 2 parchment-lined baking sheets. Bake 1 pan of cookies in a preheated 350° oven for 7 min. Press dough down slightly with the back of a soup spoon; rotate pan 180° and bake 3-5 min. more until just barely set and slightly puffy. Remove from oven and cool cookies on pan for 2 min.; move to wire racks to cool completely. Repeat with second pan of cookies.