CRUST: COMBINE all ingredients; press 2/3 cup onto bottom of each of 24 (4-inch) springform pans (or onto bottom of each of 6 [4-inch] springform pans for trial recipe). Set aside.
CUSTARD: PLACE chestnuts and 2 cups evaporated milk (or 1/2 cup evaporated milk for trial recipe) in blender; blend until smooth. Pour into large bowl.
ADD remaining ingredients, in batches, to blender (or add all remaining ingredients to blender for trial recipe); blend until smooth. Add to chestnut puree; stir.
PLACE springform pans in parchment paper-lined half-sheet pans. Fill each springform pan with 1 cup custard mixture. Bake in 375ºF-standard oven 45 to 50 min. or until knife inserted near centers comes out clean. Cool custards completely in springform pans. Refrigerate 4 hours.
TOPPING: ARRANGE 23 banana slices, in concentric circles with slices slightly overlapping, on top of each custard; sprinkle with 1 tsp. sugar. Use butane torch to brown bananas. Sprinkle custards with combined chili powder and cinnamon. Run metal spatula around rims of pans. Remove rims.