Preheat oven to 325ºF. Coat a 9 X 13-inch baking pan with cooking spray or line bottom of pan with parchment paper. Alternatively, you can use a 9 X 13-inch nonstick pan.
Grind graham crackers until fine in a food processor or place crackers in a resealable plastic bag and crush with rolling pin. Place crumbs in a small bowl.
Melt butter on stove top or in microwave and pour over graham cracker crumbs. Mix with a fork until completely moistened.
Press crumbs evenly into bottom of prepared pan and place in refrigerator while preparing pumpkin filling.
Place cream cheese in bowl of a mixer fitted with a paddle attachment or beat with an electric mixer until smooth. Add sugar and mix until incorporated.
Mix in 1 cup of sour cream until just combined and then add cinnamon, nutmeg, ginger and cloves. Add remaining sour cream and mix until just combined.
Slowly beat in each egg one at a time until incorporated, and then mix in pumpkin. (Note: For best results, all ingredients should be at room temperature and mixed as little as possible, until each ingredient is just combined.)
Pour pumpkin mixture into prepared pan, spread evenly throughout and smooth top.
Bake until set at edges, about 30 minutes. (Note: The very center will be a little loose.) Cool completely and refrigerate overnight before cutting into 18 pieces and serving.