Ok I know this childish but I had been craving Banana Custard. So I used a PALEO white sauce recipe and adapted it to make vanilla custard.
BANANA CUSTARD
200ml milk of your choice + 50ml

1 egg

50ml double/heavy cream

1-2 tsp vanilla paste

5-7 drops vanilla stevia

2 tsp arrowroot powder
1. Mix milk, egg, cream vanilla paste and stevia together in a pan.

2. Mix 50ml of milk and arrowroot powder in a separate jug and keep to one side.

3. Heat milk mixture in pan, stirring constantly, until just before boiling.

4. Remove from the heat and add arrowroot, sit in thoroughly, return to heat stir constantly until desired thickness is achieved.

5. Allow to cool slightly before you add sliced banana.