Preheat oven to 375°F. Spray 5 (8-ounce) ramekins with cooking spray. Place ramekins on a large, rimmed baking sheet.
In a medium bowl, stir together ¼ cup brown sugar, flour, and ¼ teaspoon salt. Using pastry blender or two forks, cut in ¼ cup cold butter until mixture is crumbly and pea-size clumps form. Stir in pecans. Refrigerate until ready to use.
In a large bowl, toss together apples and lemon juice.
In a large skillet, melt 2-½ tablespoons butter over medium heat. Add apple mixture, and cook, stirring frequently, until apples are almost tender, about 10 minutes. In a small bowl, whisk together ¼ cup cold water and cornstarch. Add cornstarch mixture, apple pie spice, remaining ½ cup brown sugar, and remaining ¼ teaspoon salt. Bring to a boil; cook, stirring constantly, for 2 minutes. Remove from heat. Divide apple mixture among ramekins (about 1¼ cups each). Evenly divide topping on apples.
Bake mini apple crumble pies until topping is golden brown, 15 to 20 minutes. Let cool for 5 minutes. Serve with ice cream, if desired.
Tip: Make apple pies ahead of time; chill up to 24 hours. Reheat the pies in the oven, covered, with foil; bake at 350°F for 30 minutes. Serve warm.