In a bowl set with a fine-mesh strainer, mix together the lemon slices, sugar, fresh mint leaves, rosemary leaves, and vanilla bean seeds (including the pod if you’re using one). Using clean hands, gently massage the mixture for about 2-3 minutes until the lemons release their juices and the herbs are lightly coated in sugar.

Cover the herb and lemon mixture with plastic wrap and place it in the refrigerator for at least 3-4 hours, or preferably overnight.

Using your hands, press down on the lemon mixture through the strainer to extract the juice while discarding the solids.

Transfer the strained juice concentrate into a large pitcher. Pour in 8 cups of cold water and stir to combine.

To serve, fill glasses with ice and pour the lemonade over the top. Garnish each glass with sprigs of fresh mint or rosemary.