Preheat the oven to 400°F (204°C). Lightly spray 8 regular-size muffin cups with cooking spray.
Separate the cinnamon roll dough into 8 rolls. Flatten each roll into a 4-inch round and place it into each prepared muffin cup.
Make the apple pie filling. Melt 2 tablespoons of butter in a wide skillet over medium-high heat. Add the apples and cook, tossing occasionally, until they start to soften, about 5 minutes. Stir in 2 tablespoons of brown sugar, cinnamon, and salt. Cook for 5 more minutes or until tender. Stir in lemon juice.
Make the crumble topping. Add the flour, brown sugar, and nuts to a medium bowl. Cut the butter into small cubes and then add them to the bowl. Work the butter into flour and sugar using your fingers or a fork until it is crumbly.
Divide the apple filling between the 8 cupcake cups, then top with the crumble topping.
Bake the cupcakes for 10 to 15 minutes or until bubbly, and the tops are light brown. Cool in the pan for 5 minutes, then transfer to a cooking rack. Serve the cupcakes topped with whipped cream, ice cream, or a drizzle of caramel sauce.
