Panna Cotta with Balsamic Strawberries

Ingredients

• packet (1 teaspoon) unflavored gelatin powder
  ½ unit
• cold water
  1½ tablespoons
• heavy cream

  divided
  1½ cups
• plain whole-milk yogurt
  1 cup
• pure vanilla extract
  1 teaspoon
• vanilla bean

  split and seeds scraped
  ½ unit
• + 1 tablespoon sugar
  ⅓ cup
• (4 cups) sliced fresh strawberries
  2 pints
• balsamic vinegar
  2½ tablespoons
• sugar
  1 tablespoon
• freshly ground black pepper
  ¼ teaspoon
• freshly grated lemon zest

  for serving
  1 unit