From the Williams-Sonoma Family Meals recipe book:
For the simple syrup -- 1 cup water and 1 cup sugar
1 cup fresh lemon juice (I squeezed the juice out of four Costco lemons and it came to exactly the right amount. Also if you don't have a lemon juicer, Walmart sells them for $3 and I see lovely glass vintage lemon juicers in the antique stores from time to time)
4 cups cold water
1 lemon, thinly sliced and slices seeded
To make the simple syrup, in a small saucepan, combine the water and sugar, stir to combine and bring to a boil over medium high heat. Reduce the heat to medium and simmer for 5 minutes. Pour into heatproof container, let cool completely, and refrigerate until well chilled.
To make the lemonade, pour the lemon juice into a 2 1/2 qt pitcher. Add the simple syrup to taste. If you are using a sweet lemon, such as a Meyer, you will need less syrup. Add the water. stir to blend, and then add ice. Pour into tall glasses, garnish with the lemon slices, and serve right away.
If you are like me and have a little one with just two and a half teeth, you probably have frozen strawberry puree in your freezer. I suggest adding one to two cups of freshly blended strawberry puree to make delicious strawberry lemonade! It is so good!
The recipe says that it serves six. I recommend doubling this recipe:)