Pre-heat the oven to 350 degrees Fahrenheit. Line an 8 x 8 baking pan with parchment paper, leaving an overhang on all sides.
In a medium bowl whisk the egg, vanilla, milk, sour cream and vegetable oil.
Add the flour, sugar, baking powder, cinnamon and salt and whisk again. Add the crystallized ginger and chopped lemon peel and use a rubber spatula to gently incorporate.
Pour the batter into your prepared pan and bake till a tester comes out clean, 30 - 35 minutes. Let the cake cool in the pan on a wire rack set over a piece of wax paper.
Make the glaze:
Combine the confectioner's sugar and maple sugar in a bowl. Starting with 1 1/2 tablespoons, add the lemon juice and whisk. Add more lemon juice, a bit at at time, till a thick but pourable consistency is achieved.
Pour the glaze over the cooled cake, using a small angled spatula if needed to spread it to the edges. Let the glaze set before serving.