Apple Crisp

For the topping
1 cup of Flour
¾ cup of Oats
½ cup of Unsalted Butter very cold and cut into small dices
½ tsp Baking Powder
1/3 cup of Brown Sugar
1 tsp of Cinnamon
¼ tsp of Salt

For the filling,
3 pounds of Macintosh Apples, peeled, cored and cut into big chunks
Zest and juice of half of a small Lemon
Zest and juice of 1 Orange
2 Tbsp of Flour
1 tsp of ground Cinnamon
½ cup of Granulated Sugar