Cream the butter in the bowl of an electric mixer. Add the honey and beat until fluffy and light.
Add the yolks one at a time, beating well to incorporate after each addition.
Sprinkle in the salt; then reduce the speed to low and gradually add the lemon juice so as not to splash. Mix until homogenous, but don't worry if the mixture looks curdled at this stage.
Meanwhile, fill a saucepan one-third full of water. The saucepan should be large enough to allow a mixing bowl to dip down at least halfway into the saucepan, but unable to touch the top of the water. Bring the water to a boil over high heat, then reduce heat and maintain a simmer over medium heat.
When everything is mixed, place the mixer bowl on top of the saucepan or pour into a mixing bowl that can be placed over the saucepan.
Heat slowly, whisking constantly, until the butter melts and the mixture is thick enough to coat the back of a spoon, about 10 minutes. The mixture will be 170-175°F. To test for doneness, dip a spoon in the mixture. The mixture should cling thickly to the spoon and if you drag your finger through the mixture on the back of the spoon, a clear path should remain where your finger went.
Cover and chill in the refrigerator until firm, at least 1 hour. Keep in mind that the curd will thicken as it cools.
Store in an airtight container in the refrigerator for up to 2 weeks, or in the freezer for up to 2 months.