Filling ~ Walnut butter cream

Walnut butter cream frosting
source : http://www.nosalty.hu/gazdag_diotorta_recept_1659

Ingredients
200gm ground walnut
1 Tbsp plain flour
250ml milk
100gm sugar
1 sachet vanilla sugar (or 1 tsp vanilla extract)
lemon zest from 1 lemon
100gm margarine , room temperature ( I used butter)

Method
1) In a sauce pan, mix together milk, sugars, lemon zest. Heat it just until boiling point.
Add in flour and walnut mixture. Bring it to boil again. and set aside to cool

2) Beat margarine (butter) with elec. mixer. When butter is light and fluffy, add in walnut mixture cooked earlier. Combine well and it is ready to be used as cake filling.