Before you have your Aseprite, you can always use https://www.linneart.com/pj/
You can click "browse"and check a file on your PC, without uploading it anywhere.
*edited* Sorry Honest mistake, Hard to count color when you are not using specialized pixel software, and I think my brain trick me somehow... i convinced myself it is 8 color 
Of all the entries, I think this has the most delicious looking pizza on the box! 
Unfortunately I just found out that it has 9 colours. Please edit it ASAP
@gawrone: Thank you! hmmm... I was thinking on make the font gradient hmm.. not sure how it would turn out 
Ok, noted