Do you need to grease the Swiss roll tin with oil or butter when you are making the Vanilla Shortbread?
Nigella's Vanilla Shortbread (from NIGELLA SUMMER) is based on the traditional shortbread ratios of 3:2:1 of flour:butter:sugar. The shortbread has quite a high ratio of butter for a biscuit or cookie, so usually it is not necessary to grease the Swiss roll tin (jelly roll pan) as the shortbread rarely sticks. Greasing the tin could lead to the shortbread becoming a little too crisp and coloured around the edges.
If you are worried then we would suggest lining the tin with baking parchment (parchment paper). You can just line the base of the tin with the baking parchment, cutting it to fit, as it is easy to run a knife around the shallow edges of the tin to loosen the sides of the shortbread, if necessary. Lining the tin should not change the baking time or temperature.