Preheat the oven to 325°F (or air fryer to 300*F) Lightly spray an 8x8 baking dish with cooking spray and line it with parchment paper. Spray the parchment paper.
Pour the sugar, flour, cocoa powder and cornstarch through a fine mesh sieve and into a medium bowl, to get rid of any lumps. (If you don’t have a sieve, just dump these ingredients into a bowl and it will be just fine).
Add in the chocolate chips and salt, whisk to combine everything.
In a large bowl, whisk together the eggs, oil, water, and vanilla.
Combine the dry and wet mixtures and stir until just combined, there should be some lumps.
Pour the batter into the prepared pan (it'll be thick - that's ok) and use a spatula to smooth the top. Bake for about 35-45 minutes, or until a toothpick comes out half clean, with some very moist crumbs. This step really just depends on your oven and how you like your brownies, if you’re eating them a la mode then sometimes 35 minutes is enough. At the same time, others may cook them for 45 minutes. BUT it's better to pull the brownies out early than to leave them in too long. Cool completely before slicing. Store in an airtight container at room temperature for up to 3 days. These also freeze well!
These can also be cooked in an air fryer at 300*F for 20-30 minutes. Check them at 20 minutes until cooked to your liking.
