Preheat oven to 375°F. Line a baking sheet with parchment paper or a silicone baking mat and set aside.
In the bowl of an electric mixer fitted with the paddle attachment, add the cold cubed butter, granulated sugar, and light brown sugar. Cream on medium speed until the mixture is well blended and fluffy, about 4–5 minutes.
Add the eggs one at a time, mixing after each until incorporated. Add the vanilla extract and mix until fully combined.
In a separate large bowl, whisk together the all-purpose flour, salt, baking powder, and baking soda until evenly combined.
With the mixer on low speed, gradually add the dry ingredients to the wet ingredients and mix just until no large streaks of flour remain. Do not overmix.
Add the semisweet chocolate chips and the Snickers Bites to the dough. If using a stand mixer, mix on low to medium speed for about 20–30 seconds to distribute and gently break up some of the Snickers pieces. Do not overmix. If you are not using a stand mixer, roughly chop the Snickers Bites and fold the chocolate chips and chopped Snickers into the dough by hand with a spatula until evenly distributed.
Use a medium cookie scoop to portion two mounds of dough per cookie (3 tablespoons total). Roll each portion into a ball with your hands to smooth the surface.
Place the dough balls on the prepared baking sheet, spacing them a couple of inches apart to allow for spreading.
Bake on the center rack for 14–18 minutes, or until the cookies are very lightly browned at the edges and the centers are set but still slightly soft. Avoid overbaking.
Remove the baking sheet from the oven and let the cookies rest on the pan for 5 minutes, then transfer them to a wire rack to cool completely.