Place the softened butter and sugar in a large bowl or the bowl of a stand mixer. This is best done with a stand mixer or a hand mixer. Using the paddle attachment on the mixer, beat the sugar and butter on medium speed until light and fluffy, about two minutes.
Add the pure vanilla extract and beat in.
Add the tapioca flour or cornstarch and all-purpose flour to the bowl and mix until just combined.
Add the cream to the bowl and mix in. At this point, to prevent overbeating the dough, you can simply use a spatula to mix the cream evenly into the dough.
The cookie batter at this point might look a little crumbly but it will be soft and will hold together nicely when you form it into a ball.
Refrigerate the dough for an hour.
Once the dough has chilled, preheat oven to 350 degrees Fahrenheit. Use a cookie press fitted with a disc of your choice, or a pastry bag fitted with a piping tip ½ inch in diameter, to press out cookies at a distance of about an inch. The cookies will puff up and spread slightly during baking, but not much.
Sprinkle colored sugar or sprinkles on the cookies, if desired. If icing the cookies, or sprinkling them with powdered sugar, do it after the cookies have baked.
Place the cookie sheet in the oven and bake 10 minutes or until very lightly brown at edges. You don't want much color on these cookies. Let the cookies cool 2-3 minutes on the baking sheet. Then, carefully, using a spatula because they will still be soft, transfer the cookies to a cooling rack where they will continue to firm up.
If icing the cookies, do it after they have cooled thoroughly.