Prep: Preheat oven to 350°F. Line a 12-cup muffin pan with liners.
Simmer Peaches: In a saucepan, combine peaches (with syrup), brown sugar, vanilla, and cinnamon. Simmer for 5-6 minutes until syrup thickens. Set aside to cool.
Make Crumble: Mix crumble ingredients with a fork until clumps form. Refrigerate while prepping the rest.
Bake Crust: Mix crust ingredients. Press 1.5 tbsp into each liner. Bake for 5 minutes, then cool completely.
Make Filling: Beat cream cheese until smooth. Mix in sugar, sour cream, and vanilla. Add eggs one at a time on low speed, then the flour. Do not overbeat.
Assemble: Fill liners almost to the top with batter. Use a slotted spoon to place 2-3 peach slices on each (drain syrup well). Top with 1.5 tbsp of chilled crumble.
Final Bake: Bake for 18-20 minutes until set (no wobble).
Chill: Cool at room temperature, then refrigerate for 2-3 hours to set before serving.