Preheat oven to 325-degrees. Place 1 cup of white chocolate chips in a microwave safe bowl. Microwave on 50% power in short increments, 20-30 seconds, and stop to stir between passes until the chips blend smoothly. Be careful--white chocolate can burn fast! Set aside to cool.
In a large mixing bowl, beat together the sugar, butter, vanilla, and eggs until they're creamy. Mix in the melted chips. Stir in flour, baking soda, and cream of tartar. Add the pumpkin spice chips and the pecans.
Use a cookie scoop or tablespoon to place dough in rounded lumps on cookie sheet. Bake 10 to 12 minutes, until the edges begin to turn very light golden brown. Cool on the sheet for several minutes, then move to a rack to cool.
ON NOM NOM!