📖 Instructions

1. Prepare Your Baking Sheets & Oven: First things first, preheat your oven to 375°F (190°C). This is important for an even bake. While it's heating, line two large baking sheets with parchment paper. This prevents sticking and makes cleanup a breeze!
2. Combine Dry Ingredients: In a medium-sized bowl, whisk together the all-purpose flour, baking soda, and salt. Make sure these are thoroughly combined. This ensures the leavening agent and seasoning are evenly distributed throughout the dough. Set this bowl aside for now.
3. Cream Butter & Sugars: In a large mixing bowl, either using a stand mixer with the paddle attachment or a hand mixer, cream together the softened unsalted butter, granulated sugar, and light brown sugar. Beat on medium speed for about 2-3 minutes, until the mixture is light, fluffy, and noticeably pale. This step is *super* important for incorporating air, which contributes to the cookie's soft texture.
4. Add Eggs & Vanilla: Scrape down the sides of the bowl. Add the large egg and the egg yolk, one at a time, beating well after each addition until fully incorporated. Then, mix in the pure vanilla extract. Don't overmix here; just combine until smooth.
5. Incorporate Dry into Wet: Gradually add the dry ingredient mixture (from step 2) to the wet ingredients in the large bowl. Mix on low speed, just until *barely* combined. Be careful not to overmix the dough! Overmixing develops too much gluten, which can lead to tough cookies. Stop mixing as soon as you no longer see streaks of dry flour.
6. Fold in Chocolate Chips: Now, gently fold in your chocolate chips and chopped chocolate bars using a rubber spatula. You want a generous mix of chocolate, so don't be shy!
7. Scoop the Dough: Using a 2-tablespoon ice cream scoop or a large spoon, drop rounded balls of dough onto the prepared baking sheets. Space them about 2 inches apart, as they will spread. If you want truly thick cookies, gently press the tops of the dough balls down slightly with your palm.
8. Bake to Gooey Perfection: Place one baking sheet into the preheated oven. Bake for 9-11 minutes. Here's the trick for gooey middles: you want the edges to be set and lightly golden, but the centers should still look soft, puffy, and slightly underbaked. They might even look a little wet in the middle. This is *exactly* what you want!
9. Cooling is Key: Remove the baking sheet from the oven and immediately (and I mean immediately!) gently tap the baking sheet on your countertop a few times. This helps deflate the cookies slightly and creates those beautiful crinkly edges. Let the cookies cool on the baking sheet for 5-10 minutes. They will continue to set and firm up during this time.
10. Transfer and Devour: After cooling on the sheet, carefully transfer the cookies to a wire cooling rack to cool completely. Or, better yet, enjoy them warm! There's nothing quite like a warm, gooey chocolate chip cookie. Repeat with the second baking sheet, or freeze any remaining dough for later.