Line a 9x9-inches baking dish with parchment paper and grease it with baking spray or butter, set aside.
In a large bowl, using an electric mixer beat together: flour, sugar and butter until creamy.
Add salt, eggs, lemon juice and lemon zest to the flour mix. Beat on medium speed until smooth, about 3 minutes. Stop once to scrape the sides and bottom of the bowl with a spatula. Pour batter into the prepared baking dish.
Bake in the preheated oven for about 25 minutes, start checking after 20 minutes of baking. A toothpick inserted in the center should come out clean and the sides of the cake will start to get golden brown, while the center will be settled.
Remove from oven and cool in the baking dish for 10 minutes, after that transfer the cake to a cooling rack and continue cooling.
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 the mixture is too thick, add more lemon juice, 1 tablespoon at a time.
Spread the glaze over the cooled brownies. Let it settle.
Slice into bars and serve.
Store in the fridge in an airtight container or wrapped in plastic wrap for up to 4 days.