Combine in a large mixing bowl the 2 cups oats, 1 cup flour, 1/3 cup brown sugar, 3/4 cup melted butter and 1/4 teaspoon salt
Press the mixture in the bottom of a 10" spring form pan
Bake for 10 minutes then remove from oven
Turn oven down to 325
Make the cheesecake filling by beating the cream cheese with 2/3 cup of sugar until it is mixed well, then add the eggs (one at a time) and be sure to scrape down bowl between additions
Add vanilla and mix well
Pour mixture over crust
Prepare apples by combing them with the cinnamon, nutmeg, salt and sugar
Place apples on top of cheesecake mixture
To make the streusel combine 1 cup brown sugar, 1 cup flour, 1 cup oats, pecans, butter and 1/2 teaspoon salt, then use a pastry blender or a fork to make medium sized crumbs
Place crumbs over apples
Bake for 80-90 minutes and test for doneness with a long toothpick. (Mine took about 80 minutes and it is OK if it jiggles slightly)
Remove from oven and let cool on counter. Refrigerate until cold (6 hours or overnight)