In a large mixing bowl, using an electric mixer, cream together the softened dairy-free butter, neutral oil, light brown sugar, and granulated sugar on medium speed until light and fluffy, about 2-3 minutes. Scrape down the sides of the bowl as needed.

Add the large egg and egg yolk, one at a time, mixing well after each addition until fully incorporated. Stir in the vanilla extract.

In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix.

Fold in the dairy-free chocolate chips with a rubber spatula until evenly distributed.

Cover the bowl with plastic wrap and chill the dough in the refrigerator for at least 30 minutes, or up to 1 hour. Chilling helps the cookies hold their shape and develop flavor.

Preheat your oven to 375°F (190°C). Line two large baking sheets with parchment paper.

Scoop rounded tablespoons of dough (about 1.5-2 tbsp each) onto the prepared baking sheets, leaving about 2 inches between cookies. A small ice cream scoop works perfectly for this.

Bake one sheet at a time for 10-12 minutes, or until the edges are golden brown and the centers are set but still look slightly soft. For extra chewiness, underbake slightly.

Remove from the oven and let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.

Repeat with the remaining dough.