Preheat the oven to 375 F. Line baking sheets with parchment paper. Set aside.
In a medium size saucepan, add the butter (cutting into cubes beforehand helps the butter cook more evenly).
Cook the butter over medium heat for a couple minutes to brown. You will hear the butter sizzle and then it will start to foam. When it gets to that point, use a wooden spoon or spatula to move the foam out of the way so you can see the butter changing color. You want to cook the butter so that it gets to a light brown and has brown specs. You’ll truly be able to smell when it’s done. It’s heavenly.
Turn the heat off and let the melted butter cool slightly, about 10 to 15 minutes.
In a medium-size mixing bowl, whisk together the flour, baking soda, salt and baking powder. Set aside.
In a medium size mixing bowl, combine the brown butter, brown sugar and granulated sugar. Mix until combine. You can do this with a stand mixer, a hand mixer, or even a wooden spoon because the butter is melted.
Add the eggs and vanilla and mix until combined.
Stir in the flour mixture until no streaks of flour remain.
Add the oats and the butterscotch chips and fold to combine.
Using a large cookie scoop, make 3.5-ounce cookie dough balls. (If you make smaller cookies, just remember the baking time will decrease a little).
I place all the pre-made cookie dough balls on one baking sheet and then freeze the dough for 15 minutes.
Freezing the dough helps the butter set, which helps the cookies keep a little more shape and height as they bake.
Once the dough is chilled, place 8 balls of dough on a baking sheet. I do three down the sides and two in the middle, so there’s plenty of room between them all.
Bake for 7 to 8 minutes. The cookies will look slightly underdone on top. That’s okay.
As soon as the cookies are out of the oven, place the caramel pieces in the center of the cookies. It’s okay if you push down on them a little. Load them up with caramel pieces and then sprinkle with flakey salt.
Allow to cool completely (or at least 30 minutes) before eating so the cookie centers set a little.