Shallot and Spring Onion Tart with Crunchy Hot Butter Pastry

My family always teases me about my sensual descriptions of tarts but the very name makes it hard to avoid. I think onion is my favourite kind of savoury tart; they are sweet, soft and altogether irresistible — there I go again.

The pastry here is very easy. You do not have to roll it out and there is no advantage in baking it blind — it is naturally crisp.