01 - In a small saucepan, combine the raspberries, peach slices, granulated sugar, and water. Bring to a simmer over medium heat, stirring gently until the sugar fully dissolves and the fruit softens, about 4 to 5 minutes. Remove from heat and strain through a fine mesh sieve into a bowl, pressing firmly to extract as much juice as possible. Discard the solids and set the syrup aside to cool.
02 - Place the black tea bags in a heatproof pitcher and pour the boiling water over them. Steep for 5 minutes, then remove and discard the tea bags. Allow the brewed tea to cool to room temperature.
03 - Add the freshly squeezed lemon juice and honey or agave syrup to the cooled tea. Pour in the prepared fruit syrup and stir thoroughly until all the sweetener is dissolved and the mixture is well blended. Taste and adjust sweetness or acidity as desired.
04 - Transfer the pitcher to the refrigerator and chill for at least 1 hour, or until the beverage is thoroughly cold.
05 - Fill individual glasses with ice cubes. Pour the chilled iced tea lemonade over the ice. Garnish each glass with fresh raspberries, peach slices, and mint leaves if desired. Serve immediately.