Interesting how two quite remote French regions have very similar local specialities. Brittany and le Pays Basque each have their own version of round, buttery and melting, sweet shortcrust tarts.
I might, at the risk of my friendship with both sides, say they are virtually the same confection. The difference is in the egg yolk content and in using melted or only softened butter. Inside, vanilla crème pâtissière or cherry preserve in one, nothing or prune conserve in the other. Both boast a swirly pattern (or the Basque lauburus) on top, rendered in an extra egg yolk.
The pastry is awfully rich, buttery and heavy, like a posh relative to shortcrust. Easy to put together, especially that, unlike shortcrust, it doesn’t need chilling in the fridge - mix and press into the dish, smoothing out the crumbs. It’s a bit more fiddly when you want to bake it with a filling - hence my version is plain and easy.