We all have different ideas about how tart lemon bars should be. We think this recipe has the perfect balance of sweet and tart flavors, but If you find that you'd like to make yours sweeter, don't add extra sweetener. Swap out some of the lemon juice for orange juice. This will keep the bars just tart enough, but sweeter than if you used all lemon juice. Note that oranges have more carbs than lemons, so your carb count will be a bit higher if you choose this route.