What logo has a double circle with letters H B inside that's on the bottom of a decorative microwave safe bowl made in China?

The logo you're describing is likely the one associated with the brand "Homer Laughlin," particularly their "H B" mark. This brand is known for producing ceramic dinnerware, including decorative microwave-safe bowls. The double circle and the letters "H B" are characteristic of their branding, often found on items manufactured in China.