Set all your ingredients out at least an hour in advance. You want everything at room temperature to make it easier to work with.
2/3 c packed brown sugar
1 1/2 teaspoons pumpkin pie spice
1 lb cream cheese
Beat together until well blended then start adding each of these one at a time.
2 large eggs
2 large egg yolks
1 cup pumpkin puree
Bake in your 8" springform pan with a crumb crust 30 minutes at 350, then reduce to 325 for another 10 - 15 minutes.
Let cool and refrigerate for at least 6 hours, preferably 24 before serving.