Heat oven to 375 F. Grease muffin cups or use foil or paper baking cups. Finely chop the ginger. Finely grate the lemon peel so you have 2 tablespoons. In a large bowl, beat butter and the 1 cup sugar with a wooden spoon or electric mixer until pale and fluffy. Beat in eggs, one at a time. Add ginger and lemon peel. Stir baking soda into yogurt or buttermilk; it will start to bubble and rise up. Fold flour into ginger mixture one third at a time, alternating with the yogurt. When well blended, scoop into muffin cups. Bake 18 to 20 minutes, or until lightly browned and springy to the touch. While muffins bake, mix lemon juice and the 2 tablespoons sugar in a small dish. Stir until sugar dissolves. When muffins are baked, re