By Emily Monaco When Chef Charles Phan decided to bring rich, creamy Vietnamese coffee to San Francisco, he never expected he would need to journey to India to make it happen. It all began seven years ago, with a collaboration between Phan and Kevin Bohlin of Saint Frank Coffee, who began supplying Phan’s Slanted Door seven years ago. Finding Bohlin was a challenge in and of itself, given Phan’s checklist of must-haves in a coffee supplier: ethical sourcing, top-quality ingredients and, of course, the perfect flavor. “We tried a few different coffee roasters who are local to the Bay Area but d…