Grease and line a loaf tin ( 9 in x 5 in; or 23 cm by 13 cm.)
Juice the half of lemon, then zest it.
Start heating oven to 180 C / 350 F / Gas Mark 4.
Beat together in a large bowl the butter, sugar and lemon zest until creamy. Then beat in the eggs one at a time. Stir in the grated beet, cranberries, lemon juice and nutmeg. Then stir in the flour.
Pour into the loaf tin, spread evenly.
Bake for 60 to 70 minutes until a toothpick or skewer comes out clean. Remove from oven, let cool in tin, then turn out onto a rack. Slice thickly to serve.