Preheat the oven to 350 F / 180C.
Line a baking sheet with parchment paper or aluminum foil. I used one large sheet and one medium sheet.
Sift together flour, salt, baking soda, cinnamon powder in a bowl.
In a separate bowl beat soft butter and sugars till creamy and fluffy.
Add egg, essence and beat until combined.
Add flour mixture to wet ingredients and beat until well combined.
Fold in oats and butterscotch chips.
Drop spoonful of batter onto a cookie sheet or shape cookies with hand and place on cookie sheet. I did the latter.
Bake for 8 – 12 minutes for chewy cookies and longer for crispy cookies. I baked for 12 minutes. I baked in two batches, 1 large cookie sheet and one medium cookie sheet. Check notes below.
Let the cookies cool for few minutes on cookie sheet, transfer to cooling rack and let cool completely.
Store in airtight container.