-
In a heavy saucepan, combine the first 6 ingredients (butter, sugar, brown sugar, evaporated milk, pumpkin, pumpkin pie spice); cook mixture over medium heat.
-
Bring mixture begins to a boil, stirring constantly. Boil mixture until candy thermometer reaches soft-ball stage (234-243 degrees). It's best to use a candy thermometer but if you don't have one you can boil the mixture until it gets foamy and once it's foamy boil for an additional 4-6 minutes.
-
Remove pan from heat; stir in chocolate chips until melted. It's important to remove it from the heat so that the chips don't get overheated and turn grainy.
-
Add the marshmallow cream, pecans, and vanilla and stir to combine well.
-
Pour into a buttered 13x9 inch baking pan; cool to room temperature.
-
Cut into squares; store in the refrigerator in an air-tight container. I like eating it at room temperature.