In a 2 cup measuring glass pour in 1 Cup of boiling water.

Measure in 1 cup of granulated sugar.

Stir until dissolved, clear and no longer gritty.

Set aside.

Zest 2 lemons (or more if you want very strong lemon) into the blender.

Squeeze juice from lemons until reaching a half cup of juice and add to blender.

Add in 1 cup of simple syrup and 3-4 Cups of ice.

Blend.

Taste for proportions and sweetness.

Then blend on high until thick and icy. If needed add more ice or a few tablespoons of water for correct consistency.