In the bowl of a stand mixer, cream together the butter, brown sugar and granulated sugar until fluffy and smooth, about 1 minute. Add in the eggs, one at a time, beating well after each addition. Beat in the molasses and vanilla extract, mixing well. Beat in the baking powder, baking soda, cinnamon, and flour, mixing well. Lastly, beat in the oats and butterscotch chips until just combined.

Cover and chill the dough for at least 45 minutes, up to overnight. This is mandatory as it prevents the dough from spreading too much during baking.

Preheat oven to 350 degrees F. Line 2 baking sheets with parchment paper or silicone liners. If you allowed your dough to chill longer than 1 hour, let it soften for about 5-10 minutes at room temperature before scooping. Scoop out the dough using a 2-Tablespoon-size cookie dough scoop and place 2" apart on the baking sheets.

Bake for 10-12 minutes, rotating the pans halfway through baking time to ensure even baking. Cookies may appear slightly underdone when you pull them out; this is normal as they will continue to set up as they sit on the pans. Cool for about 15 minutes on the pans, then gently transfer to a wire rack to cool completely.