mmm delishyous i mean... delicious D You shaded it very well! I just think that maybe the chocolate is too orange. Or it's 25% cocoa xD ...well, you shouldn't care with this. The tutorial is SO well explained and i'm sure that will be useful for too many people ^^ congratulations!
Yeah but there are still some things that some pixellists don't understand I've looked through your pixel art before ^^ you're not bad, but I think you should try to make your colours a little more contrasting and your shadows a bit bigger and more defined.
Don't be afraid to try something new, you won't know unless you try. If they're too close it doesn't look right either, just don't dither basic shadows either, otherwise if the colour is too dark it looks dotty. Dithering isn't really that useful I find, unless it's trying to gradient something, otherwise its not really needed, it doesn't work as well for doing folds etc.