Preheat oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat.

Measure 2 tablespoons (1 oz) melted butter and allow it to cool slightly so it is warm, not hot. In a small bowl, whisk together the cooled melted butter, 2 tablespoons brown sugar, and 1 heaping tablespoon (18 g) granulated sugar until combined.

Add 1/4 teaspoon vanilla extract and either 1 large egg yolk OR 1 tablespoon whisked whole egg (use one option, not both). Whisk until smooth.

Measure 1/3 cup (40 g) all-purpose flour (by weight or with the spoon-and-sweep method), 1/8 teaspoon baking soda, and 1/8 teaspoon salt (if using salted butter, reduce the salt by half). Put these dry ingredients in a separate bowl. If you are making the Triple Chocolate version, add 1 tablespoon (5 g) cocoa powder to the dry ingredients.

Add the dry ingredients to the wet mixture and stir just until combined and no dry streaks remain; do not overmix.

Choose your mix-ins and fold them into the dough: - Classic Chocolate Chip: fold in 1/4 cup (1.5 oz) semi-sweet chocolate chips. - Sea Salt & Caramel: fold in 1/4 cup (1.5 oz) semi-sweet chocolate chips and 2 tablespoons chopped baking caramels. - Triple Chocolate: fold in 2 tablespoons (0.75 oz) semi-sweet chocolate chips and 2 tablespoons (0.75 oz) white chocolate chips.

Scoop the dough onto the prepared baking sheet. For a single large cookie to share, place the entire dough mound on the sheet and gently shape into a round. If you prefer smaller cookies, divide the dough into two portions and space them apart on the sheet.

If making the Sea Salt & Caramel version, sprinkle a pinch of sea salt on top of the shaped dough before baking.

Bake for 11 to 14 minutes, until the top of the cookie looks mostly set and the edges are beginning to brown.

Remove from the oven and allow the cookie to cool on the baking sheet for 5 minutes before transferring to a plate. Enjoy.