Wash peaches thoroughly. If peeling, score an X on the bottom, boil for 30-45 seconds, then transfer to ice water and slip off skins. Halve, pit, and dice into bite-sized pieces.
Toss diced peaches with 1 teaspoon lemon juice to prevent browning and brighten flavor. Set aside half for topping; blend the other half until smooth for a puree layer if desired.
In a mixing bowl or jars, combine chia seeds, milk, maple syrup, vanilla, cinnamon, and yogurt if using. Whisk vigorously to distribute seeds evenly.
Let mixture sit at room temperature for 5 minutes, then whisk again to break up any clumps. Cover and refrigerate for at least 2 hours, but preferably overnight.
After setting, stir the pudding. If too thick, add a splash of milk. If too thin, let it set longer. Assemble with peach puree, chia pudding, and fresh peach slices.
Top with granola, a drizzle of honey, fresh mint, or other desired toppings. Serve immediately or refrigerate for up to 30 minutes before serving.