Nectarine Jam - cooking recipe

Ingredients

4 pounds nectarines - peeled, pitted, and chopped
2 tablespoons lemon juice
3 cups sugar
1 (1.75 ounce) package fruit pectin (such as Sure-Jell(R) Pectin Light for less or no sugar)
3 drops almond extract, or to taste

Preparation

Inspect 5 half-pint jars for cracks and rings for rust; discard any defective ones. Immerse in simmering water until jam is ready. Wash new, unused lids and rings in warm soapy water.
Measure finely chopped, peeled nectarines; you should have 4 1/2 cups. Add to a heavy pot and immediately mix with lemon juice so they don't turn brown.
Combine 1/4 cup sugar and fruit pectin in a bowl. Add to nectarines in the pot and stir well. Slowly bring mixture to a full rolling boil that does not stop bubbling when stirred. Add remaining 2 3/4 cups sugar and stir to dissolve, making sure to scrape over the bottom of the pot. Boil for exactly 1 minute, stirring constantly.
Remove from heat and stir in almond extract.
Pack nectarine jam into the prepared jars, filling to within 1/4 inch of the top. Run a clean knife or thin spatula around the insides of the jars to remove any air bubbles. Wipe rims with a moist paper towel to remove any spills. Top with lids and tightly screw on rings.
Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars 2 inches apart into the boiling water using a holder. Pour in more boiling water to cover jars by at least 1 inch. Bring to a rolling boil, cover, and process for 10 minutes.
Remove the jars from the stockpot and place onto a cloth-covered or wood surface, several inches apart. Let rest for 24 hours without moving the jars. Gently press the center of each lid with a finger to ensure the lid does not move up or down. Remove the rings for storage and store in a cool, dark area.