Preheat the oven to 180 C / Gas 4. Lightly grease and flour two 900g loaf tins.
In a large bowl, beat the eggs with sugar, oil, milk, orange zest and vanilla extract. Toss the cranberries in a little flour then stir into the cake mixture. Sift in the flour, baking powder and salt and mix until well combined then fold in the walnuts.
Pour the cake mixture into the prepared loaf tins.
Bake for 50 minutes until a skewer inserted in the centre comes out clean. Remove from the oven and allow the loaves cool fully before slicing and enjoying.
The loaves will keep for several days if stored in an airtight container.