Prepare your jars and jalapeños. Wash your canning jars, lids, and bands thoroughly with hot soapy water. Sterilize jars by placing them in a boiling water canner for at least 10 minutes. Keep them hot until ready to fill. For the jalapeños, wash them well, then slice them thinly. Remove seeds for less heat or leave some in for more heat.

Zest about 2-3 of your oranges, aiming for about 2 tablespoons of zest. Juice all 6 oranges until you have approximately 3 cups of fresh orange juice. Strain the juice through a fine-mesh sieve to remove any pulp or seeds.

In a large, heavy-bottomed pot, combine the prepared jalapeño slices, orange zest, 1 cup of water, and 1/2 cup of apple cider vinegar. Bring to a boil, then reduce heat and simmer for 10-15 minutes.

Carefully pour the jalapeño and zest mixture through a fine-mesh sieve set over a clean bowl, pressing down on the solids to extract as much liquid as possible. Discard the solids.

Return the infused liquid to the clean pot. Add the 3 cups of strained orange juice. In a separate small bowl, whisk the pectin powder with 1/4 cup of the measured granulated sugar to prevent clumping.

Stir the pectin-sugar mixture into the pot with the orange and jalapeño liquid. Bring to a full, rolling boil over high heat, stirring constantly.

Quickly stir in the remaining 3 3/4 cups of granulated sugar. Stir continuously until fully dissolved. Boil hard for exactly 1 minute.

Remove the pot from the heat. Check for set using a cold metal spoon or the wrinkle test with a plate from the freezer.

Skim off any foam that forms on the surface of the jelly using a clean spoon. Ladle the hot jelly into the hot, sterilized canning jars, leaving 1/4 inch of headspace. Wipe jar rims clean.

Place lids and bands on the jars, tightening finger-tight. Process in a water bath canner for half-pint jars for 5 minutes.

Remove jars from the canner and let cool completely for 12-24 hours. Check seals by pressing the center of each lid.