Thanks for your request, Sarah. Generally speaking, it's advisable to swap a solid fat for a solid fat or a liquid fat for a liquid fat, so olive oil is best used as a replacement when melted butter is called for. It's a less successful replacement when butter is called for in solid form, since it can't be creamed or whipped like butter can. We have started to do some similar dairy-free testing, however, and have included coconut oil in our tests, which is a little more versatile. You might be interested to see the results we got with biscuits and more generally in breakfast treats. Mollie@KAF

• Reply