Start by spooning dollops of Nutella onto a lined baking sheet, spacing them about an inch apart. Freeze for at least 30 minutes.

Cream cold diced butter with brown and granulated sugars until light and fluffy. Beat in eggs one at a time. Gradually blend in flour, baking soda, and salt until just combined.

Weigh out 125g portions of dough, roll into balls, flatten slightly, and place a frozen Nutella dollop in the center. Fold dough over filling until enclosed.

Arrange cookie balls on a lined baking tray, space them out, and freeze for at least 30 minutes.

Preheat oven to 350°F (175°C). Bake frozen cookie balls for 12-14 minutes until edges are golden and centers are slightly soft.

Let cookies rest on the baking sheet for 15 minutes before transferring to a cooling rack.