– ¼ teaspoon sugar white, granulated – 2 tablespoons lukewarm water – ¼ teaspoon instant yeast – ½ cup whole milk [118 milliliters] plus an extra tablespoon for egg wash – 1 egg medium (plus one egg yolk for egg wash) – ½ stick unsalted butter [57 grams], melted, plus extra butter for greasing pan – 1 ½ cup all-purpose flour [204 grams] plus extra flour for dusting work surface – 1 teaspoon salt – 2 cups grated strong cheddar [240 grams] divided