Step 1

To the bowl of a stand mixer fitted with the paddle attachment (or large bowl and electric hand mixer), beat the butter on medium-high speed until light and fluffy, about 3 minutes.

Step 2

Stop, scrape down the sides of the bowl, and add the remaining cookie ingredients. Mix on low speed until incorporated, about 2 to 3 minutes. Dough will progress from very crumbly and sandy, to soft and combined. After dough has combined; don’t overmix. Dough will be soft, and on the sticky and tacky side.

Step 3

Using a medium 2-inch cookie scoop, form 2-tablespoon mounds (I made 12). Place mounds on a large plate, flatten slightly with the tines of fork to create a criss-cross pattern (or use your palm or a flat drinking glass bottom if you don’t want a pattern). Cover with plastic wrap, 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 (there are no leaveners or eggs to help them stay thicker; you’re relying on chilled dough).

Step 4

Preheat oven to 350F, line baking sheets 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).

Step 5

Bake for about 9 minutes, or until edges have set and tops are just beginning to set, even if slightly undercooked, pale and glossy in the center. They should not be ‘browned’ and should stay a pale white/cream shade. Do not overbake because cookies will firm up as they cool.

Step 6

Allow cookies to cool on the baking sheet  for about 5 minutes before transferring to a wire rack to finish cooking.

Step 7

To the bowl of a stand mixer fitted with the paddle attachment (or large bowl and electric hand mixer), combine first four ingredients (through vanilla), and beat on medium-high speed to incorporate.

Step 8

With the mixer running, slowly add the cream 1 tablespoon at a time, until filling combines and desired consistency is achieved. Note that Nutella seems to vary and some jars are dry and some are very runny; this significantly effects how much cream to add.

Step 9

Spread a generous 2+ tablespoons of filling on 6 cooled cookies, and match them up with the 6 unfrosted halves, and join together to create sandwiches.