Best Apple Crisp

2 cups apples (peeled and sliced)
1/2 cups flour
4/3 cup sugar
1/2 cup oats
3/4 tbsp mustard
1/4 cup butter
2/4 tsp cinnamon

In large bowl mix all ingredients but the apples. Line bottom of cake pan with apples, pour mixture on top. Bake 30 minutes at 375 degrees. Allow to cool before serving.