Step 1: Prepare the strawberries. Rinse the fresh strawberries thoroughly under cold water. Hull them (remove the green tops) and quarter them. If your strawberries are very large, you can cut them into smaller pieces to help them break down faster.
Step 2: Combine ingredients. In a medium saucepan, combine the quartered strawberries, granulated sugar, and water. Stir gently to combine.
Step 3: Simmer the mixture. Place the saucepan over medium heat. Bring the mixture to a gentle simmer, stirring occasionally to help the sugar dissolve. Once simmering, reduce the heat to low and continue to cook for about 10-15 minutes. The strawberries will soften and release their juices, and the syrup will thicken slightly.
Step 4: Mash the strawberries. As the mixture simmers, use a potato masher or the back of a spoon to gently mash the strawberries. This helps to extract more flavor and color from the fruit. You can mash them as much or as little as you like, depending on whether you prefer a smoother or slightly chunkier syrup.
Step 5: Add lemon juice. Remove the saucepan from the heat. Stir in the fresh lemon juice. The lemon juice brightens the strawberry flavor and helps to preserve the vibrant red color of the syrup.
Step 6: Strain the syrup. Place a fine-mesh sieve over a bowl. Pour the strawberry mixture through the sieve. Use a spoon or spatula to press down on the solids in the sieve, extracting as much liquid as possible. Discard the remaining strawberry pulp (or save it for another use, like stirring into yogurt or oatmeal!).
Step 7: Cool and store. Allow the strained strawberry syrup to cool completely to room temperature. Once cooled, pour the syrup into a clean, airtight bottle or jar. Store in the refrigerator for up to 2-3 weeks.