Preheat oven to 350˚F, grease and line a 11x15 inch pan with parchment paper or foil.
Base
In a bowl mix 3 cups flour and ¾ cup brown sugar. Shred or cube 1 cup butter into dry ingredients and blend with a pastry cutter, or a fork, until crumbled.
Add mixture into prepared pan, spread evenly, and press down with a measuring cup, press the edges with your fingers.
Bake for 15 minutes, remove from oven and cool.
Streusel
Using the same bowl as the apples, mix ½ cup brown sugar, 1 cup flour, 1 cup oats, and 1 teaspoon cinnamon. Add ⅔ cup butter and blend until crumbled. Set aside.
Cream Cheese Mixture
In a mixing bowl, blend 16 ounces cream cheese and ½ cup granulated sugaruntil fluffy. Add 2 eggs and 1 Tablespoon vanilla extract then blend again until smooth, scraping the bowl as you mix. Set aside.
Apples
Wash, dry, core, and slice 5 small green apples into small pieces. Place in mixing bowl, add ¼ cup granulated sugar, 1 teaspoon apple pie spice, and 1 teaspoon cinnamon. Mix and set aside.
Assemble
Pour cream cheese mixture on top of the baked base.
Sprinkle apples evenly over the cream cheese layer.
Top with struesel, being careful to distribute evenly over entire pan.
Bake
Bake for 40 minutes. Remove and set on baking rack to cool.