GP Diner occupies a 2,138-square-foot former burger stand on South Coast Highway 101 in Encinitas's Old Encinitas district, operating under the Buona Forchetta restaurant group founded in 2011. Roman-style pizza al taglio arrives in rectangular cuts from a high-hydration dough program developed alongside the Neapolitan ovens at sister location Buona Forchetta - Encinitas up the road in Leucadia. The split-concept layout divides the building into a pizzeria-gelateria on one side and a retro 1950s-style diner on the other, with Italian-inflected comfort dishes designed by the former founder of Carnitas Snack Shack. House-churned gelato rotates through seasonal flavor profiles using imported Italian bases, a production method shared with the original Gelati & Peccati concept that also supplies JoJo's Creamery customers seeking artisan frozen desserts along the coast. Highest-complexity items include a 72-hour cold-fermented Roman teglia dough hydrated above 80 percent and baked in steel pans at 300°C for a glassy crumb structure.