Preheat the oven to 350°.
Spray the bottom of a 9x13 in pan with non-stick cooking spray.
In medium bowl, add the cookie mix, butter, flour, and one egg. Beat the mixture until it is crumbly and well combined. Press the mixture into the sprayed pan and set aside.
Peel and cut the apples into cold water mixed with a few tablespoons of lemon juice.
Meanwhile, In a medium bowl, beat the eggs, sugar, cream, salt and 1/4 c. flour until smooth.
Drain the apples and toss them in the remaining 1/4 c. flour. Layer the floured apples over the sugar cookie crust. Pour the custard over the apples.
In your food processor, add all of the streusel ingredients and process just until it is a dry crumbly consistency. Sprinkle the streusel mixture over the apples and custard.
OPTIONAL - Sprinkle extra chopped pecans on the top.
Bake at 350° for 50-60 minutes (the center will still be slightly jiggly, but the edges should be set) Allow to cool to room temperature before serving.
Store leftovers refrigerated.