Note to future readers: this question was rightly closed as off-topic (too open-ended), but based on the advice below I ended up making a version of this grapefruit marmalade with cardamom, turmeric and ginger with the following modifications:
Added a couple of fingers of sliced fresh turmeric. If you choose to do this, learn from the mistakes I made in my first trial: wear disposable gloves and slice it on a glass board with a thick layer of disposable buffer (e.g. multiple sheets of clingfilm). I peeled mine, but I recommend just washing the skin as you will stain and clog up your peeler.
Ground my own cardamom. Not essential, but if you love cardamom I find that gives a superior flavour. Bust open the pods by crushing them with something solid and flat, fish out the black seeds and run them through a coffee grinder. (Haven't blind tested this, so it could well be a placebo effect.)
Made a double quantity and strained it through muslin or cheesecloth. You'll need a big pan, or make two separate batches if you want to play it safe. You lose a lot of the volume, but it's essential for a transparent result.
The result is a clear, shockingly vibrant yellow-orange liquid that might have a lot of sugar, but is dominated by a pleasant acidity, heat and pungency.
Thanks to everyone who suggested turmeric, which was essential for the perfect colour. If I'd had more time, I might have prototyped one of the more savoury recipes, and would love to hear from anyone who does. I'd particularly like to locate a recipe for the "JAP mustard" mentioned in the comments; the best I found was this one for "mustard custard".
In a couple of months, I will be attending a housewarming hosted a friend who is a big fan of Key/Visual Arts anime. In honour of this, I plan to recreate an infamous—albeit fictional—recipe: Akiko's special jam.
It would be silly (and rather cruel!) to try and reproduce the recipe from the show; this is left intentionally ambiguous and is known to be quite unenjoyable. Instead, I plan to make something which reproduces some of the key characteristics while remaining palatable.
These are my objectives in order of importance:
- It must be suitable for vegetarians.
- It must be bright, vibrant yellow. (Gold/orange are acceptable but not preferred.)
- There should be no obvious chunks, seeds or discolourations.
- The consistency should be thick but largely smooth.
- Rather than appearing to be a thick puree, it should have the syrupy translucency of a traditional jam or jelly.
- It should be a novel but enjoyable accompaniment for a sandwich.
- Preferably, it should not be overly sweet—though I am willing to compromise on this for aesthetics.
Where I need help
The main questions I'm debating and would like some help with are:
- What ingredients can I use for the desired colour and taste?
- What type of preserve works best with those ingredients?
- What techniques, tips or tricks could help me obtain the desired consistency and appearance?
I am a novice to jam-making and have only tried my hand at it a couple of times, so any ideas, direction or commentary will be very much appreciated.
What I've considered already
I will be trialling and refining recipes well in advance but would like to narrow down the candidates before I start experimenting. Here are some of my initial thoughts:
Yellow pumpkin/squash: I've seen recipes which get pretty close to the desired colour, though less jelly-like than I would prefer—and it would certainly taste interesting.
Yellow tomato jam/chutney: just the flesh without seeds may work well and should taste interesting; however, I'm unsure how well it would hold its colour and I'm unsure how hard it would be to get the right consistency.
Mango chutney: this would be quite sweet, unfortunately, but I've seen several recipes online that look very similar in appearance and texture to what I'm trying to achieve. Another drawback is that it may not work well on sandwiches.
Kaya: this would absolutely be sweeter than I want, but it is also delicious, unusual to Western tastes and can be made to look pretty bright. I'm concerned that it may be more opaque than what I'm going for, however.
Lemon curd: this would do in a pinch, but is still very sweet and a bit pedestrian.
Jam vs jelly vs curd vs chutney vs…: I'm keeping my options open about what sort of preserve to make, and am not sure which would work best.