Blueberry breakfast buns

Dough

• 110 g white sugar
• 20 g fresh yeast or 2 tsp dried instant yeast
• 2 eggs
• 100 g full cream milk
• 370 g baker's flour, plus extra for dusting
• 50 g unsalted butter, softened
• 1 tsp natural vanilla extract
• 1 pinch sea salt

Filling

• 250 g fresh blueberries or frozen blueberries, thawed and dried with paper towel
• 70 g white sugar
• 30 g plain flour
• 1 egg, lightly beaten, for brushing