As a convert to making marmalade using the whole fruit method, I was keen to get another batch made before the Seville oranges disappeared from the shops.
I'd several jars of membrillo in the store cupboard and hoped that by adding some of the quinces subtle flavour to the marmalade I'd create something a bit special.

This twist also gives a historical nod to the origins of marmalade as the word derives from marmelo, the Portuguese word for quinces. The original marmalade is in fact thought to have been quince jam.

I used the same recipe as before, from  Delia Smith's website, with the addition of the membrillo at the start of the boiling stage. 475g was just what I had in the jar, it's about a third of the weight of oranges, but I wouldn't want to add much more than that as it might start to overpower the recipe. The membrillo is of course at least 50% sugar so no need to add any more.
It should be possible to use frozen quince pulp, which I would thaw it out first and boil up with the citrus pips and flesh, then strain the whole lot through the muslin. This would need extra sugar adding in a similar weight ratio as for the oranges (2 sugar:1 fruit)
Anything up to 250g of fruit should be fine, if you want to add any more then cut back on some of the weight of oranges as large quantities of marmalade can be difficult to get hot enough to reach setting point.

  See here for the whole fruit marmalade with quince recipe in detail.

Recipe Costs

£2.70 1.35 kg seville oranges
£0.70 2 lemons
£2.51 2.7 kg granulated sugar
£2.23 475 g membrillo

£8.14 Total

£2.03 per kg of marmalade

The oranges are scrubbed first and then put in a preserving pan with 3 litres of water, and the lemons.

After they've been brought to the boil the top of the pan needs to be made steam tight to retain as much of the liquid as possible. I joined together two strips of foil and folded them around the rim.

After 3 hours of simmering, and resisting the temptation to peak, the fruit are nicely poached. Amazing how resilient the skins are, even after cooking for so long very few have split. Be careful if you poke them with a knife at this point, I had one spray hot juice at me.

When the oranges have cooled down a bit they can be cut in half and the softened pips and flesh easily scraped out using a metal spoon.

The peel is put to one side and the pips and flesh put in a new pan with 500ml of the poaching liquid.
Open up the lemons and remove the pips and flesh, and add this to the orange flesh, discard the lemon peel.

This is then simmered for ten minutes to extract the pectin, then strained through muslin and a sieve. The liquid is put back in the preserving pan and the pulp discarded.

While the pulp is simmering the peel can be sliced. This is where the poaching again helps, very little effort (and a good sharp knife) is needed to reduce a bowl of half oranges ...

... to a pile of sliced peel, which is added back to the preserving pan.

I stopped at this point and had a nights sleep, leaving the pan covered with a cloth on the stove top.

The sugar is pre-warmed in the oven, which helps it dissolve when added to the pan.

The poaching liqueur, pectin rich liquid, peel and sugar are all combined in the preserving pan...

... then gently brought to the boil, stirring to make sure all the sugar dissolves.

At this point I added the membrillo, chopped up a bit to help it dissolve quicker.

The marmalade is then gently boiled for 3 - 4 hours until it has reached setting point. This is tested for this using the wrinkle test on a plate taken from the freezer.
By this time the preserve has turned a rich dark colour and was smelling delicious.

Allow to cool for half an hour, so the peel doesn't float to the top, then pot in sterilised jars.

The finished marmalade has flecks of quince in it as well as the citrus peel, this doesn't bother me but could be avoided by using quince pulp and boiling it up with the orange pips and flesh, then straining through muslin, just remember to add more sugar to the preserving pan.

Recipe Timings

15 minutes First Preparation
3 hours Simmering

40 minutes Second Preparation
3 hours Simmering
30 minutes Standing

15 minutes Bottling

Taste Test

A subtle taste of quinces as hoped for, there is certainly more complexity in the overall flavour.