To the bowl of a stand mixer fitted with the paddle attachment (or large mixing bowl and electric mixer) combine the butter, sugars, egg, vanilla, and beat on medium-high speed until creamed and well combined, about 4 minutes.
Stop, scrape down the sides of the bowl and add the cream, and beat on low speed until well combined, about 1 minute.
Stop, scrape down the sides of the bowl and add the flour, pumpkin pie spice, corn starch, baking soda, optional salt, and beat on low speed until just combined, about 1 minute.
Stop, scrape down the sides of the bowl, and add the pecans, and beat on low speed until just combined, about 30 seconds.
Using a large cookie scoop, 1/4-cup measure, or your hands, form approximately 14 equal-sized mounds of dough, roll into balls, and flatten slightly. ** (see tips below)
Place mounds on a large plate or tray, cover with plasticwrap, and refrigerate for at least 3 hours, up to 5 days. Do not bake with unchilled dough because cookies will bake thinner, flatter, and be more prone to spreading.
Preheat oven to 350F, line a baking sheet with a Silpat or spray with cooking spray. Place dough mounds on baking sheet, spaced at least 2 inches apart (I bake 8 cookies per sheet).
Bake for about 10 minutes, or until edges have set and tops are just set, even if slightly undercooked, pale, and glossy in the center; don’t overbake. Cookies firm up as they cool.
Allow cookies to cool on baking sheet for about 10 minutes before serving. I let them cool on the baking sheet and don’t use a rack.
Notes
**Tips: Strategically place a few pecans on top of each mound of dough by taking pecans from the underside and adding them to top. Pecans that bake directly on the baking sheet on the undersides of the cookies could become overly browned; try to shield them with dough or relocate to tops/sides.Storage: Cookies will keep airtight at room temperature for up to 1 week or in the freezer for up to 6 months. Alternatively, unbaked cookie dough can be stored in an airtight container in the refrigerator for up to 5 days, or in the freezer for up to 4 months, so consider baking only as many cookies as desired and save the remaining dough to be baked in the future when desired.Dough base adapted from Candy Corn White Chocolate Softbatch Cookies.