Blogger-entrepreneur Andrew Sullivan — who left The Daily Beast earlier this year to launch his own reader-supported site and has since raised over $800,000 from his supporters — is launching the next phase of the site on Monday: a monthly subscription-only magazine of longform journalism called Deep Dish. Sullivan told readers about the new feature in an email over the weekend.

Although some of the content on Sullivan’s regular Daily Dish website is available to non-subscribers — who are prompted to pay when they click a link to see more than just an excerpt — the blogger said the new monthly magazine will be exclusively for subscribers. “Free-riders can’t see it,” Sullivan’s email said. “We’ve erected a real paywall to keep them out, unlike our leaky meter system on the blog.”

Sullivan has talked in the past about his desire to have a magazine-style format for longer pieces. He said…