Whisk the 480g flour, 7g instant yeast, 50g sugar, and 1½ tsp salt in a large bowl. Add the 240ml warm milk, 60ml warm water, and 1 egg. Mix until a shaggy dough forms, then knead in the 57g butter a tablespoon at a time. Knead for 8 to 10 minutes by hand (or 6 minutes in a stand mixer) until smooth and slightly tacky.

Place the dough in a lightly oiled bowl, cover, and let rise in a warm spot for 1 to 1½ hours until doubled in size.

Punch the dough down, divide into 12 pieces (about 75 to 80g each), and shape each into a tight ball. Arrange in a greased 9x13-inch (23x33cm) baking dish.

Cover loosely and proof for 45 minutes to 1 hour at room temperature until the buns are visibly puffed and touching. Heat oven to 190°C (375°F).

Whisk the 1 egg yolk and 1 tbsp milk together and brush over the buns. Scatter the 200g shredded cheddar on top. Bake at 190°C (375°F) for 22 to 25 minutes until the cheese is deeply golden and the internal temperature reaches 93°C (200°F). Rest 5 minutes in the pan, then serve warm straight from the dish.