Eat Like a Dinosaur, and a similar recipe on Chris Kresser's site.
Both of their dressings uses raspberries, but I opted for some frozen local strawberries we picked earlier this summer.
My kids aren't big on salad dressing but both gave this a thumbs up. Since you can make it with frozen fruit this would be tasty all year (I can imagine it on a salad incorporating roasted squash and other fall/winter flavors).
Paleo Strawberry & Thyme Salad Dressing
adapted from Chris Kresser
1 cup fresh or frozen strawberries
1/2 cup water
5 sprigs fresh thyme
2 tbs. apple cider vinegar
1 tbs. dijon mustard
1 tbs. raw honey
1/4 cup olive oil
Place the berries and water in a small pot. Bring to a rapid simmer over medium heat. Cook for 8-10 minutes until thickened and slightly syrupy, stirring occasionally.
Put with berries in a blender and run until smooth. Strip the leaves off of the thyme and add to to the blender along with the vinegar, mustard, and honey. Blend again until smooth.
Pour berry mixture into a small bowl and slowly whisk in the olive oil.