Preheat the oven to 350 F (177 C). Line an 8x8 pan with parchment paper along the bottom and two sides.
Combine the oil and sugar in a microwave safe bowl. Heat in 30 second intervals for one minute total, stirring in between intervals. The sugar should feel smoother and less grainy than before it is heated.
¾ cup (177 ml) neutral oil (like canola, vegetable, olive), 1½ cups (300 g) granulated sugar
Once the oil and sugar mixture is warm, not hot to the touch, mix in the eggs and yolk until smooth and well combined.
2 large eggs (US), room temperature, 1 large egg yolk (US), room temperature
Mix in the vanilla extract, espresso powder, cocoa powder and salt until well combined.
2 teaspoon (10 ml) vanilla extract , 1 teaspoon instant espresso powder, ¼ teaspoon salt, ½ cup (40 g) dutch process cocoa powder
Stir in the flour until just combined. Fold in the chocolate chips until just combined.
¾ cup (90 g) all purpose flour, ½ cup (85 g) diary free chocolate chips or chopped chocolate
Evenly pour the brownie batter into the prepared pan. Bake for about 25 - 35 minutes.
Cool the brownies in the pan for 30 minutes. Remove the brownies from the pan to cool completely, slice and enjoy!