Preparation Cut tangerine and lemon wedges crosswise into 1/4-inch-thick slices. Discard seeds from fruit. Transfer fruit to large bowl. Add 5 cups water, covering fruit. Cover bowl with plastic wrap; let stand at room temperature 1 day. Transfer fruit mixture to heavy large pot. Scrape in seeds from vanilla beans; add beans. Bring mixture to boil. Reduce heat and simmer until rind is very tender and fruit begins to fall from rind, stirring occasionally, about 1 hour 15 minutes. Remove from heat. Add sugar; stir until sugar dissolves. Boil gently until mixture is 210°F, stirring occasionally, about 1 hour 20 minutes. Divide vanilla beans and boiling hot marmalade among four 1-cup jars. Cover tightly and refrigerate up to 2 months.
Preparation Cut tangerine and lemon wedges crosswise into 1/4-inch-thick slices. Discard seeds from fruit. Transfer fruit to large bowl. Add 5 cups water, covering fruit. Cover bowl with plastic wrap; let stand at room temperature 1 day. Transfer fruit mixture to heavy large pot. Scrape in seeds from vanilla beans; add beans. Bring mixture to boil. Reduce heat and simmer until rind is very tender and fruit begins to fall from rind, stirring occasionally, about 1 hour 15 minutes. Remove from heat. Add sugar; stir until sugar dissolves. Boil gently until mixture is 210°F, stirring occasionally, about 1 hour 20 minutes. Divide vanilla beans and boiling hot marmalade among four 1-cup jars. Cover tightly and refrigerate up to 2 months.