Preheat your oven to 180°C (350°F) and line a baking sheet with parchment paper.
In a large bowl, beat the softened butter and brown sugar together with a spatula or mixer for about 3 minutes until the mixture is fluffy and smells sweet and caramel-like.
Add the egg and vanilla extract to the butter mixture, and stir until fully combined; the mixture should look shiny and smooth.
In a separate bowl, whisk together the flour and baking soda, then gradually fold this dry mixture into the wet ingredients until just combined. The dough will be thick and slightly sticky.
Gently fold in the chocolate chips, distributing them evenly throughout the dough without overmixing, so the chips stay intact.
Scoop spoonfuls of dough onto the prepared baking sheet, leaving about 2 inches between each, then slightly flatten each mound with the back of your spoon.
Bake for 10-12 minutes, watching for the edges to turn a light golden brown while the centers look slightly underbaked and glossy—that’s the secret to chewy cookies.
Once out of the oven, allow the cookies to sit on the baking sheet for about 5 minutes; they will firm up slightly but remain soft and gooey in the center.
Transfer the cookies to a wire rack to cool completely or enjoy warm for an extra gooey bite.
Serve with a glass of milk or your favorite beverage and savor the melt-in-your-mouth texture of these perfectly chewy cookies.
