Crust
1 1/2 cups quick oats
1/2 cup finely chopped pecans
1/2 cup brown sugar
1/3 cup melted butter

Place oats in food processor or blender; process to consistency of flour.

Combine oats with remaining crust ingredients; press into bottom of 10-inch springform pan. Chill.

Filling
40 ounces cream cheese, softened
1 2/3 cups light brown sugar
5 eggs
1 teaspoon vanilla extract
2 cups chopped pecans, divided
Whipped cream (optional)

Beat cream cheese with mixer until fluffy; slowly add brown sugar and mix well. Add eggs, one at a time, mixing after each addition. Stir in vanilla extract and half of nuts. Mix and pour over crust. Bake at 350 degrees F for 1 hour.

Turn oven off but leave cake in oven for 30 minutes more. To reduce the chance of cracks on top surface, run a knife edge of cheesecake as soon as you remove it from the oven. Let cool to room temperature; chill for 8 hours.

Remove sides of pan. Press additional chopped pecans around sides and pipe top with whipped cream.