In a medium saucepan, combine 2 cups of sliced fresh strawberries, 1 cup of granulated sugar, and 1 cup of water. Cook over medium heat for about 30 minutes, stirring occasionally until the strawberries soften and release their juices. Strain the mixture through a fine-mesh sieve into a bowl to separate the syrup from the solids. Let the syrup cool to room temperature.

While the strawberry syrup cools, boil 2 cups of filtered water in a separate pot. Once boiling, remove from heat and steep 4 black tea bags in the water for 5 minutes. Remove the tea bags and stir in any remaining sugar from the syrup if desired.

In a large pitcher, mix the cooled strawberry syrup with the brewed tea. Add 4 cups of cold water and freshly squeezed juice from 1 lemon, stirring to blend all the flavors. Taste and adjust sweetness or tartness as needed.

To serve, fill tall glasses with ice cubes. Pour the strawberry iced tea over the ice and garnish with fresh mint and sliced strawberries.