Apple and Cheese Spelt Buns

Name: Apple and Cheese Spelt Buns
Ingredients: For the leaven:; 1 teaspoon instant dry yeast or 10g fresh yeast; 280 milliliters whole milk, at body temperature; 140 grams spelt flour; For the bun dough:; 200 grams spelt flour, plus extra for dusting; 110 grams rye flour; 1 teaspoon fine sea salt; 50 grams butter, melted; 30 grams honey; 1 medium egg; For the filling:; 1 egg, beaten, for egg wash; 200 grams grated Västerbotten or mature Cheddar cheese; 2 tablespoons caraway seeds; 1 1/2 medium apples, cored, quartered and diced into 5mm pieces