To get that carmel flavor you're looking for, use a standard white cake recipe and substitue butter for the oil, and brown sugar for the white sugar. You may also want to use milk instead of water in the batter.
To use butter, just melt it until it's liquid and drizzle in while mixing the matter.
The flavor should fall somewhere between a true caramel and a butterscotch. But then again, butterscotch gets part of its flavor from salt. If you use unsalted butter, your cake will have a more natural caramel flavor.
Also, the amount of brown sugar you use will be slightly more that if you had used white sugar, as the white variety has more sweetening power. I would add an extra 2 tbs. per cup of flour.
Good luck. If you aren't a very experienced cake maker, do a Google search for the recipe. It will give you precise measurements.
“No amount of success outside the home can compensate for failure within the home…
Check out my blog for the friendliest cooking instruction on the net. Go ahead. You know you want to.