Preheat oven to 350 degrees F (175 degrees C). Grease an 8-inch square baking pan.
In a medium bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the salt, lemon zest, and vanilla. Beat in the flour, cashews, and lemon juice until just blended.
Spread the batter into the prepared pan and bake for 35 to 40 minutes, or until a toothpick inserted into the center of the brownies comes out clean. Cool completely in the pan before cutting into bars.
Interesting Facts
Lemon zest is the finely grated peel of a lemon.
Cashews are a type of nut native to South America.