In a large mixing bowl, combine the melted unsalted butter, brown sugar, white sugar, vanilla extract, and egg. Mix gently until well combined.

Add the all-purpose flour, baking soda, and salt. Fold gently using a rubber spatula until the flour is incorporated. Avoid overmixing.

Add the chocolate chunks and fold gently until evenly distributed throughout the dough.

Cover the dough and refrigerate for 15–30 minutes to allow it to firm up.

Scoop about 1/3 cup of dough for each large cookie and roll into balls.

Place the dough balls on parchment paper and refrigerate for another 10–15 minutes.

Place a flat pan over low heat and lightly grease it with butter. Avoid using too much butter, as excess fat can cause the cookies to fry rather than cook gently.

Place the chilled cookie dough balls in the pan, leaving enough space between them. Flatten each ball gently.

Cover the pan with a lid and cook over low heat for 5–7 minutes, or until the bottoms are golden brown and the edges are set.

Carefully flip the cookies using a spatula. Cover the pan again and cook for another 3–5 minutes, or until the other side is lightly golden and the cookies are cooked through.

Transfer the cookies to a cooling rack or plate. Allow them to cool for a few minutes before serving.

Serve warm with milk, coffee, hot chocolate, or your favorite drink.