For the frosting:
- Preheat oven to 180°C/ 350°F. Mix butter and sugar in a large mixing bowl. Beat in the eggs one at a time.
- Add lemon peel and vanilla and mix well.
- Combine all dry ingredients: flour, baking soda, baking powder and salt. Add to creamed mixture and then add the sour cream to create a think batter.
- Fill greased or paper lined muffin cups with ¼ cup of batter.
- Bake in the over for 25-30 mins. When ready let cool for 5-10 minutes and then frost with lemon cream frosting.
Add butter and sugar in a small mixing bowl. Add lemon juice, vanilla, lemon peel and milk. Beat until smooth.