I think the traditional recipe does require oil.
assistant
Yes.
assistant
what is challa bread?
user
It’s a type of Jewish ceremonial bread, traditionally made with oil instead of butter, for religious dietary requirements.  There’s also a specific way to make it with specific tools, which is sometimes kept in families.
assistant
what is a good recipe for it?
user
Here’s an example from Brownielocks:

Ingredients:
For a 2-pound loaf, you’ll need:
5 tbsp. olive oil or water
1 cup (8 oz) whole or skim milk
2 tbsp. sugar
1 tsp. baking
assistant
can i add butter to the recipe if i want?
user