Double-Strawberry Buttermilk Panna Cotta - Dorie Greenspan

Ingredients

• 1 pint (8 ounces) fresh strawberries, hulled, rinsed, dried and thickly sliced
• 2 teaspoons honey
• 1/2 teaspoon balsamic vinegar
• 2 1/4 teaspoons (1 packet) unflavored gelatin
• 3 tablespoons cold water
• 1 cup heavy cream
• 1/4 cup sugar
• 2 teaspoons pure vanilla extract
• 1 cup whole or low-fat buttermilk, preferably at room temperature