Preheat your oven to 350 degrees F. This is crucial for ensuring even baking. You’ll want that heat ready to go as soon as your batter is prepared.
Line a 9×9-inch baking dish with parchment paper and grease it with baking spray or butter. This helps prevent sticking and makes for easier removal once the brownies are baked.
In a large bowl, using an electric mixer, beat together the flour, sugar, and butter until creamy. About 2 to 3 minutes of mixing should do the trick; you want a smooth and homogenous mixture.
Add salt, eggs, lemon juice, and lemon zest to the flour mixture. Beat on medium speed until smooth, about 3 minutes. It's important to stop once to scrape the sides and bottom of the bowl with a spatula to ensure everything is well combined.
Pour the batter into the prepared baking dish. Spread it evenly with a spatula, making sure the corners are well filled. This will help the brownies bake uniformly.
Bake in the preheated oven for approximately 25 minutes. Begin checking for doneness after 20 minutes. You’re looking for a toothpick inserted into the center to come out clean, with the sides of the cake turning golden brown and the center set.
Once baked, remove the cake from the oven and let it cool in the baking dish for 10 minutes. This cooling step helps the brownies firm up a bit more before transferring them.
After 10 minutes, transfer the cake to a cooling rack to continue cooling. It’s essential to let it cool completely before glazing to prevent the glaze from melting away.
For the glaze, add all the ingredients to a medium bowl and stir to combine until smooth, with no lumps. If the mixture is too thin, add more confectioners sugar, 1/4 cup at a time. If it's too thick, add more lemon juice, one tablespoon at a time, until it reaches the desired consistency.
Spread the glaze over the cooled brownies. Let it settle for a few minutes; this will create a lovely finish on top.
Slice into bars and serve. Enjoy your One Bowl Lemon Brownies, and don’t forget to share!