1-First Step: Cream the Base Cream together 1 cup unsalted cold butter (cut into small cubes) and 1 1/2 cups granulated white sugar at high speed for 3-4 minutes. Beat until light and fluffy. This builds air for soft cookies.

2-Second Step: Add Eggs Add 2 large eggs one at a time, mixing well after each. Scrape the bowl sides to incorporate fully. Eggs bind everything for fudgy texture. For vegan, mix flax eggs here.

3-Third Step: Mix Dry Ingredients Add 1/2 cup dark unsweetened cocoa powder (not Dutch processed), 1 cup cake flour, 1 1/2 cups all-purpose flour, 1 teaspoon cornstarch, 3/4 teaspoon baking soda, and 1/2 teaspoon salt. Mix on lowest speed until just combined, less than 30 seconds. Overmixing toughens dough.

4-Fourth Step: Incorporate Chips and Chill Stir in 1 cup semisweet chocolate chips by hand, reserving 1/3 cup. Chill dough in the fridge 30-60 minutes until cold but not hard. Chilling prevents spreading and helps seal the filling.

5-Fifth Step: Preheat and Prep Sheets Preheat oven to 410°F. Line baking sheets with silicone mats or parchment paper. Parchment works great as a sub. Bake one sheet at a time for even results.

6-Sixth Step: Portion and Fill Divide dough into 8 portions, about 4.5 ounces each. Weigh for uniformity. Flatten each into a disc. Place 1.5 tablespoons hazelnut spread in the center. Wrap dough around to form a sealed ball with no cracks. Use a cookie scoop for easy filling. Warm spread if stiff.

7-Seventh Step: Top and Bake Press 5-6 reserved chocolate chips on top of each ball. Place on middle oven rack. Bake about 11 minutes until surface dries and cookies look almost set but slightly darker in middle. High heat crisps edges while keeping centers gooey.

8-Final Step: Cool and Serve Cool cookies on the sheet at least 20 minutes before removing. They firm up for the best lava pull. Serve warm for molten bliss. Yields 8 jumbo treats.