The startup is housed in a garage-like space in San Francisco’s tech-heavy South of Market neighborhood, but it isn’t like most of its neighbors that develop software, websites and mobile phone apps. Its mission is to find plant replacements for eggs. Inside, research chefs bake cookies and cakes, whip up batches of flavored mayonnaise and pan-fry omelets and French toast—all without eggs. Funded by prominent Silicon Valley investors and Microsoft founder Bill Gates, Hampton Creek Foods seeks to disrupt a global egg industry that backers say wastes energy, pollutes the environment, causes disease outbreaks and confines chickens to tiny spaces....