In a medium bowl, whisk together all purpose flour, baking soda, and kosher salt.

In a separate bowl or the bowl of a stand mixer, beat butter on medium-high speed until soft and fluffy.

Add the brown sugar and granulated sugar and mix until creamy.

Mix in the egg, molasses, vanilla extract, and butterscotch flavoring.

Add the dry ingredients and mix until just barely combined, then stir in the rolled oats.

Fold in the butterscotch chips and crushed butterscotch candies.

Cover and refrigerate at least 1 hour, or overnight.

Preheat oven to 375° F / 190° C. Line a half-sheet rimmed baking tray with parchment or a silicone baking mat.

With a 1 1/2-inch cookie scoop, portion dough into golf ball-sized mounds. Roll into balls and place 2 inches apart on prepared tray.

Press a few additional butterscotch chips into the top of each ball.

Bake 10-12 minutes, or until lightly golden brown around the edges, but still soft in the middle. Do not overbake.

With a round metal cutter, quickly reshape each cookie until perfectly round.

Repeat with remaining cookie dough. Allow cookies to cool on completely on tray.

Store butterscotch cookies in an airtight container at room temperature for up to 5 days.