Proof has been a staple at nearly every farmers' market in the Valley for a reason, and it's not only because they operated out of a converted garage until last year. Jon Przybyl and Amanda Abou-Eid create their pastries and decadent breads from a single sourdough starter named Harriet that they've perfected since her start in 2010. Using a sourdough base for all their breads and pastries has additional health benefits (because of fermentation) and adds an extra dimension to the flavor. In addition, Harriet balances sweet pastry fillings in a way that a grocery store bakery could never. Przybyl and Abou-Eid also make a point to use seasonal ingredients when available. The bakers constantly rotate pastry fillings, such as a cinnamon pear danish in the spring or lemon curd filling a few weeks ago. Other must-tries at Proof, which you can find at farmers' markets in Scottsdale, Phoenix, and Gilbert, include the pain au chocolat, morning buns, and the classic country sourdough.