'- 1 can (14.5 ounces) sweetened condensed milk- 4 egg yolks- 2 tablespoons butter- 1/8 teaspoon salt, optional

'- In a bowl, combine condensed milk, egg yolks, and salt (if using). Whisk until well-blended and evenly colored.- In a wide, nonstick pan over medium-low heat, heat butter until slightly melted and still warm (NOT hot).- Add egg-milk mixture and stir well to combine.- Cook, stirring regularly and scraping sides and bottom with a spoon, for about 15 minutes or until mixture thickens to a spreadable paste.- Remove from heat, allow to cool to warm, and transfer to airtight container. Allow to cool completely before closing with lid. Refrigerate until ready to use.