How to Make It
Place a wire rack or 2 thick kitchen towels in the bottom of a large stockpot; place on stovetop.
Beat cheeses, 2/3 cup sugar, and salt with a mixer at low speed until smooth. Add yogurt; beat 1 minute. Add eggs, egg white, and vanilla; beat until mixture is smooth and creamy. Divide batter among 8 regular-mouthed half-pint (8-ounce) freezer-safe canning jars. Cover tops of each jar with foil; tightly seal edges. Place jars in prepared stockpot; add hot water to a depth of 2 inches, and cover with lid or foil. Bring water to a boil, reduce heat to medium low, and simmer 20 minutes or until cheesecakes are done. Remove jars to a rack; cool completely.
While cheesecakes cook, combine rhubarb, remaining 6 tablespoons sugar, and next 5 ingredients (through cinnamon) in a medium pan. Cook over medium-high heat until mixture boils. Reduce heat to medium low; cook 12 to 15 minutes or until mixture is very thick and liquid has evaporated, stirring frequently. Remove to a bowl, and cool completely.
Use a damp paper towel to clean the inside of jars of any cheesecake batter residue before adding the granola and jam layers. Place 2 1/2 tablespoons granola over the cheesecake layer in each jar. Top each with 2 tablespoons rhubarb jam. Place lids on jars, and freeze. Thaw at room temperature before serving.