Step 1

Using potato masher, mash sugar and half of lemon slices in large bowl until sugar is completely wet, about 1 minute.

Step 2

Add water and lemon juice and whisk until sugar is completely dissolved, about 1 minute. Strain mixture through fine-mesh strainer set over large bowl or pitcher, pressing on solids to extract as much juice as possible. Discard solids.

Step 3

Add remaining lemon slices to strained lemonade and chill for at least 1 hour. Serve.