Preheat oven to 350 degrees F (175 degrees C). Butter an 8 inch springform pan. In a small bowl, add lemon juice to milk. Stir together and let stand 5 minutes. Sift flour, baking powder, cinnamon, cloves and salt together and set aside.
In a large bowl, cream oil, orange zest and brown sugar. Add sour milk and vanilla. Add flour mixture and beat until smooth. Stir in the grated carrots and chopped nuts.
Pour the batter into an 8 inch springform or other deep 8 inch pan. Bake at 350 degrees F (175 degrees C) for 1 hour, or until a toothpick inserted into the cake comes out clean. Allow to cool.