I usually use Canva:

Pros: Extremely user-friendly, tons of pre-made templates (including cookbook/recipe book templates!), block blast excellent for quick mock-ups and visual consistency. Easy drag-and-drop interface. Has a free tier that's quite robust. You can definitely create a professional-looking ebook with it.

Cons: Less precise control over typography and layout compared to professional tools. Can feel a bit "template-y" if you don't customize enough.