Make the apricot preserves
Tip:To adapt a slow-cooker recipe to a conventional oven, follow these guidelines: add more liquid, to accommodate for greater evaporation; bring the dish to a boil over high heat in a Dutch oven, then cover the pot and put in a 350°F oven. Plan on the dish taking roughly half the time to cook in the oven as it would in the slow cooker.
Place a small plate in the freezer. With a vegetable peeler, gently peel the yellow zest from one of the lemons. Place on a small piece of cheesecloth and, using twine, tie into a bag. Add to the slow cooker. Squeeze 1⁄4 cup juice from the lemons into a strainer set over a small bowl (you’ll probably use about 1-1⁄2 lemons); discard the solids. Add the juice to the slow cooker.
Use your hands to split open each apricot; discard the pit. Once you’ve repeated with all of the apricots, coarsely chop the pile with a chef’s knife. Toss into a large bowl and use a potato masher to mash. Measure out 4 cups and add to the slow cooker, along with the sugar and salt. Stir well. Cover the slow cooker and cook the mixture on low heat for about 4 hours, until the fruit is broken down.
Pour into a large saucepan and bring to a boil over medium-high heat. Add the pectin and boil for about 9 minutes, stirring occasionally, until the pectin has dissolved and the preserves have thickened. Remove the pan from the heat and test whether the preserves have set by spooning a drop onto the chilled plate and tilting the plate. If the preserves are thick and run just a tiny bit, they’re done; if not, boil for another minute, then retest. The goal is slightly runny preserves, which are perfect for a parfait. Using a funnel, carefully transfer the hot preserves into clean glass jars. Let them stand until cool, then place in the refrigerator. The preserves will last for 2 to 3 weeks.
Make the parfaits
Into each of six parfait glasses or glass cups, spoon 1⁄2 cup Greek yogurt, then 2 Tbs. apricot preserves, then 1 Tbs. nuts. Repeat the layering and serve immediately.