First, juice all your lemons. You can do this in advance and store it in the fridge for a day if you like.
Then, make a simple syrup on the stove with which to sweeten the lemonade. Heat ½ cup water and sugar on the stove over medium heat. Stir until sugar dissolves, then remove from heat and let cool slightly.
Meanwhile, prepare your strawberries. Wash and hull them, then blend them with 1 cup water to make a purée.
With a fine mesh strainer or cheese cloth, strain out the seeds and pulp so you are left with a strawberry juice. You may need to repeat this one or two times to remove all seeds.
Combine the lemon juice, simple syrup and strawberry juice in a pitcher. Top with 4 cups cold water. Refrigerate until ready to drink!
Notes
Feel free to use frozen strawberries or store-bought lemon juice instead, but fresh will taste the best.