Line a baking sheet with parchment paper. Set aside.
In a medium bowl, whisk together the flour, salt, and baking powder. Set aside.
In the bowl of a stand mixer with a paddle attachment (or using a handheld mixer), cream together the softened butter, light brown sugar, and granulated sugar on medium-high speed for 3–4 minutes, or until light and fluffy.
Add the eggs, one at a time, mixing well on medium speed after each addition.
Stir in the vanilla extract.
With the mixer on low speed, gradually add the dry ingredients and mix until just combined, scraping down the bowl as needed.
Use a spatula to gently fold in most of the chopped Snickers bars and caramel baking bits until evenly distributed. Reserve a small handful of each mix-in for topping.
Using a 2-tablespoon cookie scoop (or spoon), drop rounded portions of dough onto the lined baking sheet. (Important: Tuck any large exposed caramel or candy pieces back into the dough to avoid burning.) Reshape into smooth balls as needed.
Press a few of the reserved Snickers pieces and caramel bits into the tops of each dough ball.
Cover with plastic wrap and chill the cookie dough for at least 1 hour, or up to overnight.
When ready, preheat oven to 350°F (175°C). Line a separate baking sheet with parchment paper.
Place the chilled dough balls on the prepared baking sheet, spacing them about 2 inches apart.
Bake for 9–11 minutes, or until the edges are lightly golden and the centers still look soft. Do not overbake; they will continue setting as they cool.
Let the cookies cool on the baking sheet for 10–15 minutes before transferring them to a wire rack to cool completely.