One way to tell if your Nutella cookies are ready is by looking for cracks on the edges. When the cookies are first placed in the oven, they will be soft and doughy. However, as they bake, the edges will begin to harden and crack. Another way to test doneness is by lightly pressing on the center of the cookie. If it springs back, it is probably ready. However, if it leaves an indentation, it needs to be bake for a few minutes longer.