Berry Jam Rolls

Ingredients

• 4½ cups (650 g) all-purpose flour, sifted
• ¾ cup (100 g) cake flour, sifted
• 2¼ tsp (1 envelope, or 8 g) instant dry yeast
• ½ tsp salt
• 4 tbsp (50 g) white sugar
• 2 cups (480 ml) milk, lukewarm
• 3 eggs
• 1 tsp vanilla extract
• ½ cup (100 ml) vegetable oil
• orange zest from one orange
• 1 cup mixed berry jam
• ¼ cup (50 g) butter (for brushing between buns and baking pan)
• 1 egg for egg wash
• powdered sugar (optional)