I'm trying to bake some rolls from scratch, but I don't want the tops of them getting brown... I'd like the tops to stay a bit softer and at most turn a light brown. Do I need to adjust the ingredients, the heat or coat the tops of the buns with something? I've tried dropping the heat to 250, but that was too low and the buns did not turn out. I tried at 350, but the tops get crunchy and too brown. It's a basic recipe with water, flour, butter, sugar, yeast and baking powder.