Preheat the oven to 350 F, position a rack in the middle of the oven. Grease a 7-inch cake tin with little butter and dust with flour to coat the pan, or you may use parchment paper.
In a medium mixing bowl, sift the flour, baking powder & baking soda. Add salt, whisk the dry ingredients until well combined. Set aside.
In the bowl of your stand mixer fitted with the paddle attachment, beat the butter and sugar on medium-high speed until light and creamy, scraping down in between, should take about 2-3 minutes. Or you can use an electric hand mixer/beater.
Add in the eggs next, one at a time, continue beating on medium-high speed.
In goes the butterscotch essence, followed by butterscotch syrup. Continue mixing on medium speed.
Now reduce to the lowest possible speed, alternately add the dry ingredients and milk, starting with flour and ending with flour. ( DO NOT OVER MIX ). Transfer the batter to the prepared baking tin.
Bake in the middle rack, for about 35 - 45 minutes or until a toothpick inserted in the center of the cake comes out clean. Cool the cake on a rack in the tin for 15 minutes, then remove from the tin and cool on the rack completely.