Letting the muffin batter sit for a while and baking the muffins at a high temperature helps them develop high tops or "crowns". I like a lot of ginger flavor so I add a little candied ginger. Feel free to leave it out or add raisins instead.
If you want to make very tall, large, muffins you can pile the thickened batter higher in the cups and make 4 large muffins.