Prep the fruit: Trim off the ends of 12 ounces fresh rhubarb. Cut each stalk in half lengthwise, then slice into ½-inch pieces. Zest 1 lemon (or orange) and juice half the citrus.
Make the jam: In a medium saucepan, add rhubarb, citrus zest, juice, ½ cup granulated sugar, ¼ cup water, 1 teaspoon vanilla bean paste, and ⅛ teaspoon kosher salt, and bring to a boil.Reduce the heat and simmer, stirring occasionally until the fruit has fully broken down and mixture has thickened, about 15 - 20 minutes.Remove from the heat and cool completely to room temperature. Chill in the fridge in an airtight container for at least 2 hours before serving.
Notes
Sugar: For a sweeter jam, use ¾ cup sugar.Variations: For a deeper color and flavor, sub 4 ounces of the fresh rhubarb with 4 ounces fresh chopped plums, raspberries, or strawberries.Serving Suggestions: Enjoy with oatmeal, yogurt, toast, or by the spoonful!Storage Notes: This is a refrigerator jam and is not intended for water-bath canning. Store in an airtight container in the fridge for 2 - 3 weeks or freeze for 2 - 3 months.