Grease a 2-quart square baking dish; arrange apple slices in bottom of dish. Sprinkle with lemon juice, cinnamon, and nutmeg. Top evenly with raisins; set aside.
Combine flour, brown sugar, baking powder, and baking soda in a large bowl. Add milk, the 2 tablespoons melted butter, and vanilla; mix well. Stir in nuts. Spread batter evenly over apple mixture.
Combine caramel topping, water, and the 1 tablespoon butter in a small saucepan; bring to boiling. Pour caramel mixture over the batter in the baking dish.
Bake in the preheated oven for 35 minutes or until set in center. Spoon warm individual servings into dessert dishes, inverting each portion. Spoon caramel-apple mixture from the pan over each portion. Makes 12 servings.
When you can not decide what kind of dessert to serve, this double-delicious pudding cake will please everyone. Served warm with a dollop of cinnamon ice-cream, it is perfection.