The trick to
making caramel sauce is to watch the sugar/water mixture and make sure
it doesn’t burn. (If it does, it’s tricky to clean up as it hardens.
Don’t pour water on it as it will splatter up! Let it cool a bit then
use hot water to melt it out of the pot. Clear the plumbing with lots of
hot water.)
I recommend a candy
thermometer when making this sauce and watch carefully as it will go
from 250 to 350 degrees pretty quick. And do not stir the sugar/water
mix. Swirl the pot!
After you add the heavy
cream, stand back! It will bubble up violently — hence the reason for
the LARGE pot. After this point, just keep cooking on low and whisking.
Patience! You’ll get there! Total cooking time is about 20 to 30 minutes — but well worth it!
Follow this slideshow — it’s easy!
Heat 1.5 cups white sugar with 1/3 cup water in LARGE heavy-bottomed pot on low heat until sugar dissolves. 
Once sugar dissolves, cook on high but do not stir — just swirl the pot every once in awhile. 
Cook to a caramel color, 350 degrees on candy thermometer — about 10 minutes. Then remove from heat. 
Add 1 1/4 cups heavy cream, warmed or at room temperature. Stand back! Mixture will bubble up violently. Add 1 T vanilla. 
Cook on low heat, whisking until smooth. Some people like to add a bit of butter and salt at this point. I think it’s good without. 
Should be like caramel satin. It will thicken as it cools. 
Store in fridge. Serve over ice cream, fruit, banana slices. Great as a dip for apple slices. Enjoy!