Preheat the oven to 350°F. Line an 18x13-inch half-sheet pan with parchment paper, leaving an overhang on the sides for easy removal. Lightly grease the parchment paper.

In a large microwave-safe bowl, combine 1 cup of the chocolate chips, vegetable oil, and red food coloring. Microwave in 20 to 30-second intervals, stirring after each, until the chocolate is melted and smooth. Set aside to cool slightly.

In the bowl of a stand mixer fitted with the whisk attachment, beat together the granulated sugar, brown sugar, eggs, and vanilla extract on high speed for 5 to 6 minutes, or until the mixture is pale and doubled in volume.

Reduce the mixer speed to low and slowly pour in the melted chocolate mixture. Mix until just combined.

In a separate bowl, whisk together the flour, cocoa powder, and kosher salt.

Spread the batter evenly into the prepared sheet pan. Tap the pan gently on the counter to release any large air bubbles. If desired, sprinkle additional chocolate chips over the top.

Bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs but no wet batter.

Let the brownies cool completely in the pan before lifting them out and cutting into squares.