My camera is maybe dying, so I couldn't get a good photo of this, which is a shame since the color is so distinctive.
You have probably had lemon curd, because if nothing else, the filling in lemon bars is essentially lemon curd that forms in the oven, stiffened with a little flour. Curd is a custard, with butter instead of milk or cream, making a spread or condiment rather than something you'd serve by the bowlful -- though everyone who makes it does seem to eat it by the spoonful.
Traditionally made with citrus, you occasionally see it made with other tart fruit -- passion fruit, pomegranate -- and even more occasionally, with other things completely, like vanilla bean. But the creamy richness of it offsets citrus the best, and because the other ingredients don't add much flavor, it makes for a great showcase for citrus. I had both Seville oranges and Yuzu to use up before they passed their prime, and basically made a list of citrus-centric preparations and then decided which I'd use the Seville for, and which the Yuzu. For now, curd landed in Camp Seville.
Seville oranges are one of several oranges known as sour or bitter oranges -- oranges that aren't suited for eating out of hand, not only because they have many large seeds but because the juice is almost as sour as a lemon's. The tradeoff is that the rind and oil are much richer in flavor than those of sweet oranges. Seville oranges are traditionally used in marmalade, while the peel is used to flavor gin, beer, and candy. I add a little Seville orange peel to the French press when I make coffee sometimes.
There are many recipes for citrus curd out there, with major differences in their approach -- double boilers are common, to keep the egg from overcooking. I used David Lebovitz's simple and effective method without a double boiler, whisking constantly with the whisk attachment on my new immersion blender. Despite the pot having a particularly thin bottom (my thick pots are unenameled cast iron, which isn't suited for acidic things like citrus), it came out terrifically -- and maybe because of the whisking, maybe because of other factors, it came out light and somewhat fluffy, instead of thick and jam-like the way I'm used to.
David's recipe uses less sugar because the Meyer lemons he uses are sweeter than real lemons; I used the same reduced sugar proportions for the same reason. I also added about a shot of Campari, and about a shot of Aperol, the combination of which gave everything a slightly embarrassed peach color.
Serving suggestion: with dense, powerful gingerbread; poundcake; or homemade biscuits.