To wonder what the butter is for in this recipe? (Tarte Tatin)

[latenightjazz]

My son made this recipe (practising his caramelisation skills for food tech at school) but missed out step 3 in the assembly section. The tarte worked out pretty well to our untrained eyes and taste buds, although the caramel was a bit darker than in the picture and a bit runny. Would the butter in step 3 have lightened its colour and helped it to set? Or not? .... www.philiptessier.com/tarte-tatin

I think the butter adds a richer taste to the caramel - sounds as if it was good anyway but it would have been yummier if the butter had been there.

Thanks. Anyone else got any thoughts?

It’s to caramelise the apples and add flavour.

Yes, it just caramelises the apples better. The traditional French recipe is often just a sugar-only caramel, so leaving out butter is okay.

Wet caramel (with butter) is more forgiving than dry (just sugar) caramel.

it’s less likely to burn while in the oven and turn into a molten bitter filth of dessert disappointment.