Preheat oven to 350 degrees. Line a 9x13 pan with foil with enough foil to hang over the edges, spray foil lightly.
In a medium bowl, whisk together flour, salt, baking soda and baking powder. Set aside.
Using a mixer, cream the butter and sugars. Add eggs one at a time until well incorporated. Add vanilla and pudding mix. Beat until light and fluffy. Slowly add the flour mixture, mix well.
Add Twix bites, chocolate chips and caramels bits, stir until combined.
Press dough evenly into prepared pan.
Bake at 350 degrees for 23-25 minutes. You don’t want to over bake these. Bake just until edges begin to turn a light golden brown. The center may still look a little underbaked, but that's ok.
If you use the Twix bites, you can leave them whole or cut them in half, whatever you prefer. I left mine whole and after mixing them in with the mixer, some of them broke into pieces, which was just fine.