When it comes to takeout from trailers, you have one motto by which you stand: meals on wheels = roach coach. You’ll be eating your credo à la mode when you step up to Spencer on the Go, the new four-wheeled French takeaway vendor. Parked at night in front of Terroir wine bar in SOMA (for now), the concept spawns from Chez Spencer owner/head chef Laurent Katgely’s desire to peddle his quick-and-easy entrees from mobile metal. Fall in line for mushroom vol au vents (puff pastry canapes), boeuf bourguignon with truffles, curried frogs’ legs, and Provençal ratatouille stew in a cup. Katgely’s going for gold with a high-minded menu, so you won’t find anything predictable — like Nutella melted on a pancake. But it’ll be the taco the town. Spencer on the Go (415-864-2191 or spenceronthego.com). Mention DailyCandy for free butterfly cookies with any purchase. Terroir, 1116 Folsom Street, between 7th and 8th Streets.