Preheat the oven to 325 degrees F. and line 2 baking sheets with parchment paper.
With an electric hand mixer and large mixing bowl or in a stand mixer fitted with a paddle attachment, combine the melted butter, brown sugar and white sugar at medium-high speed.
Add the vanilla extract, egg and egg yolk and mix again on medium-high speed until well combined.
Add the flour, baking soda and salt. Mix on low speed, until just barely combined.
Fold in the chocolate chips using a large mixing spoon.
Portion the cookie dough into balls ¼ cup in size. Arrange the balls 3 inches apart on the parchment lined baking sheets.
Bake the cookies in preheated 325℉ oven for 15-17 minutes, until the edges are lightly browned but the centers are slightly underbaked.
Remove the giant chocolate chip cookies from the oven and let them rest on the baking sheet for 5 minutes before transferring them to a wire cooling rack to cool completely.
Notes
Line your baking sheet with parchment paper or a silicone baking mat. This will prevent the cookies from sticking to the pan.
Let the melted butter cool before using it. After melting, I recommend letting it sit at room temperature for at least 20 minutes.
Cream the butter and sugars for 2 to 3 minutes. When it's properly creamed, the mixture should have a lighter color, and it should feel somewhat smooth between your fingers. If there's still a lot of graininess from the sugar, continue mixing for another minute.
Leave at least 3 inches of space between each dough ball, because it will spread!
Let the cookies finish baking on the sheet pan for 5 minutes before transferring them to a cooling rack. This allows them to set up a bit, so they don't fall apart.
The semi-sweet chips may be swapped with any other variety or flavor of chips or chocolate chunks.
The unbaked dough can be frozen. Roll into ¼-cup sized balls and freeze for up to 3 months. When ready to bake, thaw at room temperature for 30 minutes, then bake as directed in the recipe.