Can we use Harshey syrup instead of cocoa powder in a cake?

It depends on what you’re doing – hot cocoa, for example. Works nicely. Maybe for cookies, maybe not. Remember that Hershey’s Syrup is a combination of cocoa, water, corn syrup, and sugar, while cocoa powder is just cocoa powder. It’s a dry mixture, not a liquid. As a result, the liquid and dry quantities of whatever recipe you’re using must be altered. It is generally more work than I would want to accomplish. There are, however, some recipes that specifically use Hershey’s syrup instead of cocoa for things like brownies – check the Hershey website for tons of stuff using their products.

That is correct. Using Hershey’s syrup instead of coco powder would add many more calories, but you’d end up with something quite thick or dense in many recipes. Moist. Decadent. That would work well in brownie, muffin, or cake recipes, but not in others, such as mousse or something, since if it’s a lighter dish, it may mess with the “chemical makeup” of the recipe. Baking is a “science” in this sense. It’s entertaining science, but it’s science!!