Prep the peaches: Wash, peel, pit, and chop the peaches into small pieces. Blanch them for 30–45 seconds first if the skins are hard to remove.
Mix the ingredients: Add chopped peaches, sugar, and lemon juice to a large heavy-bottomed pot. Let sit for 15–30 minutes if you have time.
Bring to a boil: Cook over medium-high heat, stirring often, until the sugar melts and the mixture reaches a strong boil.
Simmer the jam: Reduce heat and simmer for 40–50 minutes, stirring often, until the peaches soften and the jam looks thick and glossy.
Adjust the texture: Remove lemon halves if used, then blend for smooth jam or mash lightly for a chunkier texture.
Test the set: Spoon a little jam onto a cold plate. If it moves slowly or wrinkles when pushed, it’s ready. If not, cook a bit longer.
Fill the jars: Spoon hot jam into clean jars, cool, and refrigerate. For longer storage, freeze or use a proper water-bath canning method.
