To the bowl of a stand mixer fitted with the paddle attachment (or large bowl and electrical hand mixer), cream together the butter, sugars, egg, and extracts on medium-high speed until very light and fluffy, about 5 minutes.

Stop, scrape down the sides of the bowl, and add the cream, zest, and blend on medium speed until incorporated, about 1 minute.

Stop, scrape down the sides of the bowl, and add the flour, corn starch, baking soda, optional salt, and blend on low speed until just incorporated, about 1 minute; do not overmix.

Add the white chocolate chips, and blend on low speed until just incorporated.

Using a medium 2-inch cookie scoop, form heaping two-tablespoon mounds (I made 20). Place mounds on a large plate, flatten mounds barely, cover with plasticwrap, and refrigerate for at least 3 hours, or up to 5 days, before baking. Do not bake with warm dough because cookies will spread and bake thinner and flatter.

Preheat oven to 350°F, line a baking sheet with a Silpat or spray with cooking spray. Place mounds on baking sheet, spaced at least 2 inches apart (I bake 8 cookies per sheet) and bake for about 8 to 9 minutes, or until edges have set and tops are just beginning to set, even if barely undercooked, pale and shiny in the center. Do not overbake because cookies will firm up as they cool. Baking longer than 10 minutes could result in cookies with overly browned undersides.

Allow cookies to cool on the baking sheet for about 5 minutes before transferring to a wire rack to finish cooking. Cookies will keep airtight at room temperature for up to 1 week or in the freezer for up to 4 months. Unbaked cookie dough can be stored airtight in the fridge for up to 5 days, or frozen 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.