Should I tell her the truth?

I have a friend who thinks she is the best cook ever and she has now decided to make it a business- cook for people... she is my very close friend. In reality, she actually does not know how to cook and her food tastes disgusting. My friend is putting so much money into starting this cooking business and she is very happy about it. I am happy for her for wanting to start a business but cooking for her isn’t it. I really don’t want her wasting her money when she can’t cook but thinks she can. Do I tell her about how her cooking really taste or I should mind my business?! I don’t want her putting all her money into this and then watch her unhappy when it does not go as planned