Roll the lemons on the counter using firm pressure to loosen the internal membranes and release more juice.
Zest 6 of the lemons. In a small bowl, combine the granulated sugar with the lemon zest. Stir and press the zest into the sugar to release the oils. Cover tightly and let sit at room temperature for 2 hours.
Transfer the sugar and lemon zest to a large heat-safe bowl.
Pour 4 cups of steaming hot water over the mixture, stirring until sugar dissolves. Cover and refrigerate for 2 hours.
Slice the 6 zested lemons in half and juice them. Set aside (you should get slightly over 1 cup).
Remove the cooled lemon sugar water from the refrigerator and stir in the lemon juice.
Place a mesh strainer over another large bowl and pour the lemonade through it to remove pulp and zest. Discard the solids.
Add 2 cups of cold water and stir.
Slice the remaining 2 lemons into thin slices.
Fill a pitcher with ice and several lemon slices, then pour the lemonade over the ice. Serve immediately.