Step 1: Wash the strawberries thoroughly and hull them. If the strawberries are very large, you can slice them in half or quarter them.
Step 2: In a medium saucepan, combine the hulled strawberries, granulated sugar, and water. Add the lemon juice if using. Stir gently to combine.
Step 3: Place the saucepan over medium heat and bring the mixture to a gentle simmer, stirring occasionally. Once simmering, reduce the heat to low.
Step 4: Continue to simmer for 15-20 minutes, or until the strawberries are very soft and mushy. Use the back of a spoon or a potato masher to gently crush the strawberries as they cook, releasing their juices and flavor. The liquid should slightly thicken and turn a rich red color.
Step 5: Remove the saucepan from the heat. Carefully pour the entire mixture through a fine-mesh sieve set over a heatproof bowl. Use a spoon to gently press the cooked strawberries against the sieve to extract as much liquid as possible. Discard the solids.
Step 6: If you desire a thicker syrup, pour the strained strawberry liquid back into the clean saucepan. Bring it to a gentle simmer over medium-low heat and cook for another 5-10 minutes, stirring occasionally, until it reaches your desired consistency. Remember, it will thicken further as it cools.
Step 7: Remove from heat and let the strawberry syrup cool completely at room temperature. Once cooled, transfer the syrup into clean, airtight bottles or jars. Store in the refrigerator.