Preheat oven to 350°. Process oats in a food processor until a fine powder forms. Add pecans; pulse until nuts are chopped. Add next 5 ingredients; pulse until mixture is moistened. Remove from processor., Fill 18 greased muffin cups with 1/3 cup oat mixture each. Using a wet 1 tablespoon measure, press mixture onto bottom and up sides of muffin cups. Bake until lightly browned, about 10 minutes. Cool on a wire rack., For filling, whisk together maple syrup and cornstarch. In another bowl, mix remaining filling ingredients, then add maple syrup mixture. Spoon about 3 tablespoons into each crust., Combine topping ingredients; spoon about 1 teaspoon onto each tartlet. Bake until dark golden and set, 35-40 minutes. Cool 10 minutes before removing tartlets to a wire rack; cool 1 hour. If desired, refrigerate before serving.