Gently melt the butter in a saucepan over low heat.

Remove the saucepan from the heat, then add the lemon juice, Splenda and egg yolks.

Place the saucepan back on the stove over low heat. Whisk the mixture constantly for a few minutes until it thickens slightly.

Taste the mixture and adjust the sweetener to your liking if needed.

Transfer the mixture into an airtight jar and refrigerate for storage.