In your blender, combine 1 cup of your cooled kumquat jam and the juice from one fresh orange. Blend until completely smooth.

Pour the blended mixture through a fine-mesh strainer to remove any pulp. You'll want about 1/2 cup of the strained liquid for the curd (reserve the leftover pulp for dehydrating into fruit roll-ups, if desired!).

Set up a double boiler. In the top bowl, melt the cubed butter over medium heat, stirring constantly.

Once the butter is melted, whisk in the egg yolks one at a time, making sure each yolk is fully incorporated before adding the next.

Now comes the fun part! Gradually whisk in the honey and lemon juice, followed by your strained 1/2 cup of kumquat jam mixture.

Keep whisking constantly for about 15 minutes. The mixture will thicken and become smooth and glossy – that's your sign it's ready!