Lightly grease a 9×13 inch baking pan with oil or non-stick baking spray.
Making sure your melted butter is cooled, add it to the oil and sugars in a medium bowl. Whisk or beat until well combined.
1 cup unsalted butter, 2 TBS vegetable oil, 1 cup granulated sugar, 1 cup light brown sugar
Add the eggs and vanilla and beat again, making sure it’s completely mixed.
4 large eggs, 1 tsp vanilla
Sift (or just pour) the flour, salt, and cocoa powder into the bowl. Fold the dry ingredients into the wet until just combined without overmixing.
3/4 tsp salt, 1 cup flour, 1 cup unsweetened cocoa powder
Pour the homemade brownie batter into your greased pan, smoothing them out with a silicone spatula.
Bake in the preheated oven for 25-30 minutes if you like your brownies to have a fudgier texture or if you want them a bit more done, leave them in for 30-35 minutes.
Let the brownies cool in the pan for 15-20 minutes. Then remove brownies from the pan and allow to cool to room temperature.
Notes
Let the brownies come to room temperature if you plan to cut the brownies into shapes. Otherwise you really can eat them whenever. Just don't burn yourself. Store in an airtight container for up to five days before getting rid of the brownies.These homemade brownies can be frozen. Cut into squares before freezing and wrap each brownie individually in plastic wrap than store in a freezer safe gallon size bag in the freezer. Then when you’re ready to enjoy, remove one individual brownie from the freezer and let come to room temperature before eating.Homemade brownies can be reheated for 10-15 seconds in the microwave or put them in a cold oven and turn it on to 350 degrees. Let the brownies heat up along with the oven and remove when warm.