a friend has just had a bit of a cooking disaster while making her usual
great raspberry muffins..thought she'd try making mango and macadamia
muffins, but still using the same basic recipe, using frozen mango chunks

here's the recipe...basically, the muffins didn't rise and she wants to know
if it was the substitution of oils which caused it, and if so, why

I've googled, and so far the impression is that macadamia oil is only used
as a flavouring rather than a substitute for other oils...nothing though on
why this might be so

TIA


friend's Raspberry muffin recipe

Sift about 3 cups of SR flour - this will make 2 trays or 24 muffins of the
common size - I vary the amount of flour if I want more or less;

Add enough sugar (I use castor) - I have forgotten but I think it is up to a
cup - I just add what I think looks right - I have also used Sweeta sugar
substitute
Blend around by hand with a wooden spoon;

Add either third of a cup of custard powder (just the ordinary not vanilla
or flavoured - this gives it a "buttery" taste) or a third of a cup of
almond slivers for an almondy taste;

Slosh in enough vegetable oil - start with half a cup - to just moisten the
dry materials with a wooden spoon stirring it around - if you add too much
oil (as I have done) the muffins will be very crumbly so add a little at a
time - the consistency of breadcrumbs is the aim and less rather than more
oil;

Add half a packet (?250 gm) of frozen Creative Gourmet raspberries - do not
thaw - or blueberries or
Mix the raspberries into the dry materials;

In another dish whisk 1 cup of buttermilk with 1 large egg (or 2 bantam
eggs)
Add to the dry materials and mix with a wooden spoon (not hard) folding
gently to moisten all the dry materials with the eggy milk. At this stage if
you mix too vigorously, or use a food processor, the muffins will be very
hard. So just blend with a wooden spoon and fold. If you add too much
milk/egg so that the mixture is a bit runny it will be OK - although not as
nice as the right amount of liquid - but you need enough milk/egg to make
sure there is no dry flour mix left. If I miscalculate and have more than 3
cups of flour, and there is just a little bit of dry materials left and I
have used up all my milk/egg, I have just added a tablespoon of milk on its
own and mix it around a bit and it is fine. Basically you can use any dairy
for this bit; if you do not have buttermilk, use whatever milk you have, or
cream, or yoghurt.

Spoon into greased (I used spray vegetable oil) muffin pan so that it is
just slightly above the top - I use a spoon that is not the largest
tablespoon but larger than a desert spoon and it is just right.

Bake in 190 degree oven for 20 minutes.