In a saute pan, heat olive oil over medium heat. Add onion and garlic and saute for 3-4 minutes until onion is translucent and garlic is fragrant.
Add chicken broth, 1 cup strawberries, and balsamic vinegar. Simmer and allow liquids to reduce by about half.
Remove from heat. Add butter pieces and chopped chocolate and gently stir until both have melted and completely become incorporated. Season with salt and pepper and add additional 1 cup strawberries.