Maria Jospeh from El Paraton had a catering van and a marque on land outside main entrance every lunch time for some time so it seems possible. Also there is personal catering for "parties" meals to your door./ takeaway! If you are resident then you have access
My experience is - You will need to register Autonimo (self employed) 500 euros so you will need an accountant - another 70 euros per month ( simplier business are charged less)
Pay National Insurance each month approx 270 euros per month and be careful what you do about an employee - more National insurance holiday and xmas pay as well as sick pay
Charge Vat (IVA) as no lower threshold I am aware of
Insurance , public liability etc
so you can see why so many Key holding and "Taxi" do not become legal , it is the client who takes the risk ( remember Bob ? prosecuted when a friend gave him a hand Fined and had to pay stamp etc until he could legally dismiss him, over a 1000 euros cost fined for employing someone without paying their stamp.etc) We have someone on the Jardines who works for the tax office and the authorities are not blind .
Having discovered all of this then being legally registerred etc is the only way to set up a business here.I have been registerred for nearly 18 months.. You do not want to admit to using an illegal business in Spain. " Do you want to take the risk"?
I await the comments