Prepare baking pan by spraying with cooking spray or greasing it. Set aside. Preheat oven to 350ºF.
Add all ingredients to a medium mixing bowl and stir until well-blended.
Pour ingredients into prepared baking pan. Smooth the top, if needed. Bake for 25-30 minutes, until the center is set and a toothpick inserted into the middle of the brownies only contains a few crumbs on it.
Let cool for at least 15 minutes, and cut into 16 squares before serving.
Notes
For the best texture: Make sure your melted butter has cooled for about 10 minutes before adding it to the bowl. If it's too hot, it can start cooking the eggs and create a grainy texture instead of the fudgy brownies we're going for.Don't overbake: These brownies are done when a toothpick comes out with just a few moist crumbs. They'll continue cooking in the hot pan after you take them out of the oven, so pulling them a minute or two early is better than leaving them too long. Nobody wants dry brownies!Let them rest: I know it's hard to wait, but giving these at least a full 15 minutes to cool helps them set up properly. They'll be easier to cut and won't fall apart when you serve them.Room temperature eggs work best: If you remember to pull your eggs out of the fridge about 30 minutes before baking, they'll blend more smoothly into the batter.Storage: Keep leftover brownies in an airtight container at room temperature for up to 4 days. You can also freeze them for up to 3 months.Make them your own: If you're not a fan of nuts, skip them entirely (they are optional) or swap in extra chocolate chips, milk chocolate, or peanut butter chips. Some of my readers love adding a swirl of peanut butter or a sprinkle of sea salt on top before baking.**Nutritional facts do not include nuts