Peel and core apples. Finely chop and slice 2 quarts. Place in separate containers
and sprinkle with lemon juice.
Place muffin mix in mixer. Combine eggs and water. Gradually add to dry ingredients
while mixing on low. Mix until dry ingredients are moistened. Add chopped apples.
For topping, combine and mix together brown sugar, flour, cinnamon, vanilla extract,
salt, 2 1/4 cups butter and walnuts until crumbly. Portion one half of batter (3
quarts) into each of two 18 x 26 x 1 inch sheet pans. Evenly sprinkle batter with
2 1/2 cups topping, top with 1 quart sliced apples, 1/2 cup melted butter, and 1
1/2 cups topping.
Bake at 375 degrees F for 30 minutes or until lightly browned.