Step 1: In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.
Step 2: In a large bowl, cream together the softened unsalted butter, granulated sugar, and light brown sugar with an electric mixer until light and fluffy, about 2-3 minutes.
Step 3: Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract, scraping down the sides of the bowl as needed.
Step 4: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix the dough.
Step 5: Gently fold in the semi-sweet chocolate chips, milk chocolate chips, caramel bits, and crushed pretzels until evenly distributed throughout the dough.
Step 6: (Optional, but recommended) Cover the dough and chill in the refrigerator for at least 30 minutes, or up to 2 hours, for best results and to prevent spreading.
Step 7: Preheat your oven to 375°F (190°C). Line baking sheets with parchment paper. Scoop rounded tablespoons of dough onto the prepared baking sheets, leaving about 2 inches between each cookie.
Step 8: Bake for 9-12 minutes, or until the edges are golden brown and the centers are still slightly soft. Do not overbake. Let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.