Chocolate, Walnut and Banana Cake

I ate my first piece of banana cake only a few months ago and absolutely loved it. I had never tried any banana muffins or cakes before and thought I should definitely make it at home one day. The day has come! Old bananas on the kitchen counter? Today is finally the day I make it. So I flipped through my baking recipe book and the internet and found many different recipes: recipes with or without milk, chocolate, nuts, oatmeal..I have decided to use the one described below, adding chocolate chips and chopped walnuts. I think it's a great combination.
For a first try, I am pretty proud.

Ingredients:
(Should serve 12people)
175gr plain flour
2 tsp baking powder
Half a tsp of baking soda (optional - I did not have nay and omitted it)
125gr unsalted butter
150gr caster sugar
2 large eggs
1 tsp vanilla extract
275gr very ripe banana
150gr dark chocolate chips
handful chopped walnuts

Preheat the oven to 180°C.
In a bowl, mix the flour, baking powder and baking soda. In a second large bowl, beat together the melter butter and sugar. Beat in the eggs, one at a time. Then add the vanilla and mashed bananas. Beat well.
Then gradually add the dry ingredients in. Finally, stir in the chocolate chips and chopped walnuts.
Pour into a greased tin loaf and bake for 50min to 1hr (to check, insert a skewer in the centre and it should come out clean).
Optional: icing the cake with icing sugar mix with water.