• Prepare a large bowl of ice water for cooling the pan after cooking the custard.
• Whisk the bulk sweetener, erythritol, pectin, salt, and any dry sweetener, if using, together in a medium bowl. Break up lumps and mix dry ingredients thoroughly.
• In a medium bowl, beat the egg yolks with a whisk until smooth. Whisk in any liquid sweetener and the half and half. Sprinkle dry mixture over egg-yolk mixture and whisk until well blended.
• Heat one-half inch of water in the bottom of a double boiler to a simmer.
• Put the custard mixture in the top pan and place over, but not touching, the hot water. Cook, stirring constantly with a heat-resistant spatula, until slightly thickened and an instant-read thermometer reads 175º to 180º F. This may take about 8 to 12 minutes.
• Scrape the sides of the pan often with the spatula and scrape off the custard that sticks to the spatula itself with a knife or a second spatula while cooking, to prevent any lumps from forming. (If you do get lumps, remove the custard from the heat and whisk vigorously until smooth.)
• Remove pan from the heat and stir in vanilla. rose extract, and color, if using.
• Strain the custard into a bowl and place the bowl in the ice bath to cool it quickly. Continue to stir until cold.
• Cover and chill the custard thoroughly (8 hours or overnight) in the refrigerator.
• Whip the egg whites until foamy and add cream of tartar (if not using a copper bowl). Continue to whip until stiff but not dry.
• In a second bowl, with the same beaters, whip the 3 cups of cream until thick but not stiff, being careful not to over beat (or it will make butter).
• Stir the custard mixture, pressing out any lumps that may have formed and gently fold the cream and egg whites into the custard.
• Churn according to the directions for your ice cream maker. (It takes about 25 minutes with my Kitchen Aid Mixer attachment.)
• Scrape ice cream into a shallow container and cover with a piece of parchment paper laid directly on top of the ice cream.
• Cover container tightly with a lid or foil and place in freezer for 2 to 3 hours to ripen before serving. If frozen for longer, let soften in refrigerator until scoop-able.

To serve:

• All homemade ice cream that has been stored in the freezer for more than a few hours needs to soften in the refrigerator before serving. The length of time depends on how solidly it is frozen and the thickness of the layer of ice cream in the container. One recipe, frozen in a 2-inch layer, may soften in as little as 10 minutes. If the layer is thicker, it may take up to 30 minutes or more. Set a timer and check it every 10 minutes until you learn how long it takes. Freezing the ice cream in several smaller containers will make it faster to bring one portion up to serving temperature and will prolong the storage life of the rest of the batch, which will not then be subjected to repeated softening and refreezing.