Is there such thing?

I want to make a coffee flavored simple syrup. At least add more coffee flavor to a chocolate cake I have made.

How would I do this? Adding espresso?

coffee extract, coffee syrup, liqueur, instant espresso powder.

Thanks Pink for the response.

What would the ratio be to the sugar and water? It's for a two layer 10" cake.

I have done this with herbs. Not to long ago I experimented with a lemon cream cake with basil mint simple syrup. It was...different, but good, in a surprising, not to be expected kind of, eye opener way. LOL...

simple syrup is always 1 to 1 ration BY WEIGHT, and then add flavor as you choose. For coffee I would add 1 Tbl trablit or espresso powder ( in a pinch folgers cystals will work just fine) and 2 oz of kaluha or Tia Maria. There are some flavors that are unlocked by alcohol. Coffee has many of those flavor compounds.