Kumara muffins

1-3/4 cups sifted flour
2 tbsp brown sugar
1 tbsp baking powder
1 tsp salt
1/2 cup coarsely chopped walnuts
2 beaten eggs
3/4 cup milk
1-1/4 cups mashed kumara
1/4 cup melted butter
sugar
cinnamon
Sift together flour, brown sugar, baking powder and salt. Add walnuts. Combine eggs, milk, kumara and butter. Mix well. Add the dry ingredients. Mix until just moist. Fill muffin pans 2/3 full. Sprinkle with cinnamon and sugar. Bake at 212°C for 30-35 minutes.