Traditional Apple Crisp

1 cup flour
3/4 cup rolled oats
1 cup brown sugar
1 tsp ground cinnamon
1/2 cup butter, melted
4 cups peeled, cored, sliced apples
1/2 cup white sugar
1 Tbsp cornstarch
1/2 cup water
1/2 tsp vanilla
1/2 tsp lemon juice
 
Preheat oven to 350F.  In a medium bowl, combone flour, oats, brown sugar, cinnamon and melted butter.  Mix with hands or stir until crumbly.  Press half the mixture into a greased 8 x 8 inch baking dish. 

In a separate bowl, sprinkle sliced apples with a bit of cinnamon and brown sugar, add lemon juice.  Add this to the baking dish on top of the oat mixture.

In a medium saucepan, combine white sugar, cornstarch, water and vanilla.  Cook, stirring until thick and clear, about 10 minutes.  Pour over apples.  Add remaining oat crumble over the apples.
 
Cover with tin foil and bake for 45 minutes until bubbly and golden.