Scald the heavy cream in heavy-bottomed pan over medium heat, stirring frequently. Add 1 t cinnamon.
The cream will begin to steam, as soon as it starts to boil, remove from heat and pour into glass bowl. Add vanilla, then whisk in powdered sugar.
In large frying pan, pour oil to ½" deep. Begin to heat over medium heat.
Process graham crackers in food processor or blender until finely ground. Pour into bowl. Add flour, cinnamon, sugar, and salt. Mix well. Separate half into another bowl.
In separate bowl, whisk eggs and ¼ c milk. Separate half into another bowl.
Once oil is hot enough for frying (flick water into it and it immediately begins to sizzle gently. If it sizzles fiercely, it's too hot.), dip peach slices into egg mixture, then cracker mixture. Repeat so you have two layers of egg/cracker mixture. Halfway through your peaches, begin using second bowls of graham cracker crumb mixture and egg mixture.
Drop slices into hot oil and let cook for about a minute. Once that side is firm and golden, flip over with tongs and let other side cook until golden. Depending on how big your pan is, you could fry 4-6 peaches at a time. Do not overcrowd pan. Place on paper towel-lined plate. Finish remaining peaches.
Serve hot with warm dipping sauce.