So, I went down to the garden and picked 2 kg (and a little more) of loquats, the ripest on the tree. 

Using a pointy knife (so that it picks the skin easily) that's also small (to be used easily) remove the skin of the loquats. 

Then, cut the loquats in half and remove the seeds and as much of the hard part that surrounds them. Then, cut into smaller pieces.

So, you are left with something like a kg of pure fruit flesh. If you use store-bought loquats, that have been cultivated, the useful quantity will surely be larger. 

Using the widest pot availabe, pour in the sugar, the apples, peeled and cut into thick slices, a glass of water (plus slightly more) and the loquats. 

Remove the peel off the lemons as well as the pith. 

Wash the peel thoroughly and using a small and pointy knife cut them into very thin strips of about matchbox size (though thinner). Add them to the pot to caramelize together with the fruit. 

If you like a vanilla aroma, you can add a little at this stage. I used cinnamon which I added later on. 

Place the pot over heat, cover with the lid, set to low heat and relax with a cup of coffee. 

You should check on your pot from time to time, to see when the fruit is mashed. Make sure to stir it with a wooden spoon occasionally so that it doesn't stick. That took about 45 minutes (loquats proved to be hard, maybe it was my fault for keeping the heat too low). 

The good housewifes of olden times used to pass these mashed fruits from a sieve to get a thicker pulp. I personally prefer a more firm texture with the pieces of fruit tender enough for you to feel them. So, I passed it through a food mill. 

Then I added the cinnamon powder, 1/2 tsp vanilla and let everything simmer for an additional 10-15 minutes shaking the pot (not stirring with a wooden spoon) so that the jam doesn't stick to the bottom. Halfway through that, add the juice from the peeled lemons. 

To check if the jam has set, there are various methods. I usually use that of the drop (place a drop of jam -a very small quantity- on a small plate and place it in the fridge. After a while remove it and tip it slightly. If the drop doesn't move or moves slowly, it's ready. In any other case repeat the process until you realize that the jam has set. You can also check the newest tip from  sitronella, here.

Fill your jars almost to the top (I had 4 of 500 g each). I also added a little liqueur on the top to cover the jam (we have so much sour cherry liquer that we use it in everything that we make). It doesn't allow air to get to the jam and I personally like the taste.  

Cut pieces of greaseproof paper as many as the jars, slighly larger than the mouth of the jar and place them under the lid before you close it so that it is firmly sealed. 

The jam is ready to consume even on the next day. But remember, you made it to preserve the fruits not consume it while there are still fresh fruits available.