Sprinkle brown sugar, sugar, cinnamon, corn starch, lemon juice and nutmeg over apples.
Stir until apples are coated then add pecans. Stir.
For the Caramel Sauce
In a small heavy bottom pan, melt butter over low heat.
Stir in brown sugar and milk.
Bring to a boil over low heat and continue stirring constantly for 12 minutes.
Remove from heat and add 1 tsp of vanilla. Stir.
Let caramel cool for 10 minutes. Pour over apple mixture and stir (save a small amount to drizzle over the top. You will have to heat it up again so that the sauce is easy to pour).
Pour into an ungreased 13 x 9 baking dish.
For the Topping
In a medium mixing bowl, whisk flour, sugar, brown sugar, baking powder and salt together.
Using a pastry blender, mix butter into flour mixture until crumbly.
Pour in boiling water and stir until combined.
Spoon mixture over apples and spread making sure to cover all the apples.
In a small bowl, mix sugar and cinnamon together and sprinkle on top.
Bake for approximately 35 minutes, or until topping is golden brown.
