Walla Walla Sweet Onion Marmalade

About 2 1/2 pounds Walla Walla onions (or other sweet onion, such as Vidalia)
1 1/2 cups apple juice
3/4 cup red wine vinegar
1 tablespoon finely minced fresh garlic
2 teaspoons rubbed sage (optional)
1 teaspoon salt
1/2 teaspoon ground white pepper
1/2 teaspoon yellow mustard seeds
Heaping 1/4 teaspoon crushed red pepper flakes
4 cups granulated sugar
1/2 cup firmly packed light brown sugar
1 1.75-ounce box Sure Jell For Lower Sugar Recipes (see note)
1 teaspoon butter, margarine or vegetable oil

Wash 7 half-pint canning jars and keep hot until needed. Prepare 2-piece canning lids as manufacturer directs.

Peel the onions. To create strips that are about 1/4 inch thick and about 11/2 inches long, cut each onion into quarters lengthwise, from stem through the root end. Then cut crosswise down through each quarter chunk about every 1/4 inch. Cut enough onion to measure 7 cups. Place the prepared onions in a 6- to 8-quart heavy-bottomed pot. Stir in the apple juice, red wine vinegar, garlic, sage, salt, white pepper, mustard seeds and red pepper flakes, and mix thoroughly.

Measure the granulated sugar into a bowl, then remove 1/4 cup and set aside in a small bowl. To the larger amount of granulated sugar, add the brown sugar and mix. To the 1/4 cup of granulated sugar, stir in the pectin. Stir the pectin-sugar mixture into the onion mixture in the pot. Add the butter (the fat reduces foaming). Place the pot over high heat; bring the mixture to a full rolling boil, stirring constantly. Immediately stir in the remaining sugar mixture. Bring the mixture to a full rolling boil and then boil for exactly 5 minutes, stirring constantly. Remove from heat; skim off foam if necessary.

Ladle the hot marmalade into 1 hot jar at a time, leaving 1/4 inch head space. Wipe jar rim with a clean, damp cloth. Attach lids. Fill and close remaining jars. Process in a boiling-water canner for 10 minutes (15 minutes at 1,000 to 6,000 feet; 20 minutes above 6,000 feet). Remove and let cool overnight on the counter without disturbing the jars.

Alternatively, omit the boiling-water processing and simply store the jars in the refrigerator.

Note: This commercially prepared pectin used to be called "Sure-Jell Light" fruit pectin. It's designed to be used with recipes that contain at least 25 percent less sugar than is required with other fruit pectin products.