Lemme start off by saying that I adore your art style. It's vibrant and colorful, and very much in the style in the show, while still being original enough to call your own.
Derpy's arm looks a bit odd in the last panel, however, though that's probably just nitpicking on my part, and I'll chalk it up to the cartoonish style.
Now, while the art of this comic is wonderful, the joke...well, to be blunt, it's stale.
It's not that it's bad, it's just boring. The punchline is literally, "Derpy loves muffins", which has been absolutely done to death a million times over within this fandom. Vinyl's reaction doesn't really seem to fitting either. She looks like she's utterly heartbroken, which I find is a bit of an over reaction to a friend disliking a restaurant.
First of all i have to say this. The first, second and last panel could be neater, and i don't really like Vinyls reaction to Derpy leaving. This is very good, and i love it, but i guess it could be neater. Otherwise, i love it! I don't know why you've added Vinyl into the comic, because she isn't really a friend of Derpy's. I think this was done very well, but maybe you could have gone a little slower to make it look better? Great art though, and keep up the good work.