Step 1: Prepare the Molten Filling
Begin by preparing the core of your treats. If you are using a spread like peanut butter or chocolate hazelnut cream, scoop 12 individual tablespoon-sized dollops onto a parchment-lined baking sheet. Place the sheet directly into the freezer for at least 30 minutes until the dollops are completely solid. This crucial actionable tip ensures the filling does not melt into the dough before the exterior has a chance to bake.Step 2: Whisk the Dry Ingredients
In a medium-sized mixing bowl, vigorously whisk together the all-purpose flour, baking soda, and fine sea salt. Whisking not only combines the elements but also aerates the flour, making your final baked goods noticeably lighter. Set this bowl aside so it is ready the moment your wet ingredients are perfectly combined.Step 3: Cream the Butter and Sugars
In the bowl of a stand mixer fitted with a paddle attachment, combine the softened European butter, dark brown sugar, and granulated sugar. Beat on medium-high speed for about three to four minutes until the mixture turns pale and fluffy. Scrape down the sides of the bowl, then add the eggs, the extra egg yolk, and the pure vanilla extract. Mix on low speed until just incorporated to avoid incorporating too much air, which can cause the dough to collapse later.Step 4: Stuff and Shape the Dough
Gradually add your dry ingredients to the wet mixture, mixing on the lowest speed until just a few streaks of flour remain. Gently fold in the semi-sweet chocolate chips by hand using a silicone spatula. Divide the dough into 12 equal portions. Flatten one portion in the palm of your hand, place your frozen filling block in the center, and carefully wrap the dough around it. Roll it into a smooth ball, ensuring there are absolutely no cracks where the filling could escape.Step 5: Chill and Bake to Perfection
Place the stuffed dough balls onto a baking sheet and refrigerate for 60 minutes. While they chill, preheat your oven to 350 degrees Fahrenheit. Arrange the chilled dough balls on parchment-lined baking sheets, spacing them about three inches apart. Bake for 11 to 13 minutes, or until the edges are golden brown but the centers still look slightly soft and underbaked. Let them cool on the baking sheet for 10 minutes before transferring to a wire rack.
