4 pounds pears (unpeeled), cored, cut into 1-inch chunks
1/2 cup dry white wine
2 tablespoons fresh lemon juice
1 1/2 cups sugar
4 orange slices
1 lemon slice
4 whole cloves
1 vanilla bean, split lengthwise
1 cinnamon stick
1/2 teaspoon ground cardamom
Pinch of salt
Combine pears, wine and lemon juice in heavy large saucepan. Cover and simmer until pears are soft, pushing unsubmerged pears into liquid occasionally, about 25 minutes. Force through food mill or coarse sieve to remove pear peel. Transfer to processor and puree.
Return puree to heavy large sauce-pan. Add remaining ingredients. Stir over low heat until sugar dissolves. Increase heat to medium and boil gently until mixture thickens and mounds slightly on spoon stirring often, about 50 minutes.
Discard fruit slices, cloves, vanilla and cinnamon. Spoon butter into hot canning jar, filling only to 1/4 inch form top. Immediately wipe rim, using towel dipped into hot water. Place lid on jar; seal tightly. Repeat with remaining jars.
Arrange jars in large pot. Add boiling water to pot so that at least 1 inch of water covers tops of jars. Cover pot and boil rapidly 15 minutes. Remove jars from pot. Cool to room temperature. Press center of each lid. If lid stays down, jar is sealed. (If lid pops up, store butter in refrigerator.) Store in cool dry place up to 1 year. Refrigerate after opening.