Skillet Cinnamon Buttermilk Bread w/ Vanilla Bean Strawberry Rhubarb Jam

Ingredients

• 1/4 cup warm water (110-115°F)
• 1 1 (0.25oz) package (7g) or 2 1/4 teaspoons Red Star Active Dry Yeast
• 1 tablespoon granulated sugar
• 1/2 cup warm buttermilk (110-115°F)
• 1/2 tablespoons table salt
• 1/4 cup unsalted butter (melted and slightly cooled)
• 3 cups bread flour, divided (all-purpose flour works well too)
• 1/4 cup butter (room temperature)
• 2 tablespoons ground cinnamon
• 1/2 cup granulated sugar
• Powder sugar for dusting
• 1/2 cup diced rhubarb
• 1 cup diced strawberries
• 1/4 cup granulated sugar
• Juice of 1 lemon
• 1 vanilla bean pod (split lengthwise)
• Additional buttermilk for brushing