If a US recipe specifies 'vegetable oil' what type of oil should I use in the UK?
Peanut (groundnut) oil is a great option.

In the US vegetable oil generally means soybean oil or a soybean oil blend. The main things are that it be neutral (little or no taste of its own), with a high smoke point. On those scores, you can't do much better than peanut oil.

I have not used rice bran oil.

Yellow squash generally means this:



(the long one)

It can also mean the other yellow vegetable in the picture or this:



What it is not, is butternut:



That is a different flavor entirely. Yellow squash is more like zucchini, butternut squash is more like pumpkin.

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