70vg/30pg 3% nic with 10% apple pie, 2% cinnamon, 1% brown sugar and 1% sweetener. Tasted awful
That explains why it tasted awful, 10% FA Apple Pie and 2% (assuming FA) Cinnamon is FAR too strong. I've posted this in here multiple times, if you're using FA concentrates, download the tasting notes PDF that HIC (HeadInClouds) did to look for the mixing percentages. It's on the 1st page of this thread in my mixing guide.
Try (all FA) 4% Apple Pie and 2% Marzipan. You can add 1% Custard too or 1% Jamaican Rum to make it a little boozy.
Try this as well:
Capella (CAP) Cinnamon Danish Swirl v2 - 5.5%
FA Apple Pie - 2%
FA Fresh Cream - 1%
I've made this before and it's delish. Give it a few days for the cinnamon in the Danish Swirl to settle down though.
PS. don't add sweetener to your mixes. If the recipes good enough you shouldn't need it. No recipe is good if you need to mask it with a bunch of sweetener (Element Liquids, I'm looking at you).
__
Edit: Just saw you got it from Darkstar. They don't stock FA (FlavourArt) so I'm guessing it was TFA (The Flavour Apprentice) concentrates that you bought.
Same rules apply, make an account on E-Liquid-Recipes.com to find the best mixing percentages for the concentrates you have.