Mix the flour, salt, and baking soda together. Cream the butter and sugar together in a mixing bowl, add the egg, and beat until smooth. Add the buttermilk and mix until blended, being sure to scrape down the sides.
Add the dry ingredients and mix until smooth. Stir in the grated ginger and lemon zest.
Spoon the batter into the muffin tins so that each cup is three-quarters full. Bake for 15 to 20 minutes, until the muffins are set inside and turn golden.