In a small bowl, whisk the flour, baking powder, and salt to blend. Using a stand mixer or a hand-held mixer, beat the butter and sugar on medium-high speed until well creamed. Add the egg and beat until the mixture is light and fluffy. Add the vanilla, cream, and lemon zest and mix just until well combined. Reduce the speed to medium low and gradually add the flour mixture. Mix just until well combined. Portion the dough into thirds, shape each third into a disk, and wrap with plastic. Chill in the refrigerator until firm enough to roll out (or chill overnight).
When ready to bake, cover several baking sheets with parchment and heat the oven to 350°F. Flour a work surface and have extra flour ready. Working with one dough disk at a time, roll the dough to 3/16 to 1/4 inch thick, lightly flouring the pin, the dough, and the work surface as needed to prevent sticking. Using a variety of cookie cutters, cut shapes as close together as possible. Combine and reroll scraps as necessary. Using a thin metal spatula, transfer the cutouts to the baking sheet and decorate with sanding sugars or other decorations. Bake one sheet at a time until the edges of the cookies are just beginning to turn golden, 9 to 10 minutes. Watch carefully—the cookies should remain pale except for the golden edges, so you’ll want to get them out of the oven before much browning happens. Let the cookies cool on racks.
Store the cooled cookies, well wrapped in airtight conntainers, for a few days or in the freezer for several weeks.