Add the whole eggs and egg yolks in a large saucepan and whisk together until they are homogenous. There should be no visible egg whites.

Add the granulated sugar and salt to the eggs and whisk until fully incorporated.

Slowly add the lemon juice to the egg and sugar mixture. Whisk to combine.

Over medium-low heat, cook the lemon mixture. Constantly stirring with a rubber spatula. Be sure to keep the rubber spatula touching the bottom of the pot, and ensure you are also scraping the edges of the pot.

Continue to cook the lemon curd to nappant. Nappant means when you dip the spatula or spoon into the curd, which coats the back. The curd will hold its line once you run your finger through it.

Once the curd has reached nappant, remove it from the heat and whisk or stir in your butter. I prefer the whisk to help keep the residual heat from over-cuddling the custard.

Pour the curd into a bowl or a plastic lined sheet tray. Cover with plastic wrap, ensure it touches the curd’s full surface, poke a few holes, and cool in the refrigerator. If there are any lumps in your curd, strain the hot cooked curd into the bowl or tray and proceed as usual.

Move the cooled curd into an airtight container or mason jar.