Combine the strawberries, lemon juice, and simple syrup. Allow berries to release juice by sitting in the liquid at least 30 minutes.
Add the strawberry mixture to the blender and run it on low (I used the sauce feature on my Blendtec). You can really blend it as much/little as you like, but I found this mode made it perfectly pulpy with a bit of foam. Add whiskey and swirl to combine.
Pour over ice and serve.
Notes
If you don't have simple syrup on hand, its easy to make. Just combine equal volumes of water and sugar in a saucepan and heat while swirling just until sugar dissolves. Cool before using and store in air tight container in the refrigerator.