Preheat oven to 350 degrees F. Roast the cleaned and dried pits on a baking sheet for about 10 minutes. Carefully crack pits with a hammer (a concrete surface is best here), and extract the kernel. Return kernels to the oven and roast for a 5 minutes more. Set aside.

In a large stainless steel saucepan, combine apricots and water. Bring to a boil over medium-high heat. Reduce heat and boil gently, stirring occasionally, until apricots are soft, about 20 minutes.

Working in batches, transfer apricot mixture to a food mill or a food processor fitted with a metal blade and purée just until a uniform texture is achieved. Do not liquefy. Measure 6 cups of apricot purée.

In a clean large stainless steel saucepan, combine purée and sugar. Stir until sugar dissolves. Bring to a boil over medium-high heat, stirring frequently, Reduce heat and boil gently, stirring frequently, until mixture thickens and holds its shape on a spoon. Stir in lemon juice and amaretto.

Meanwhile, prepare canner, jars, and lids.

Place one apricot kernel in the bottom of each jar. Ladle hot butter into hot jars, leaving ¼ inch headspace. Remove air bubles and adjust headspace, if necessary, by adding more hot butter. Wipe rim. Center lid on jar. Screw band down until resistance is met, then increase to fingertip-tight.

Place jars in canner, ensuring they are completely covered with water. Bring to a boil and process for 10 minutes. Remove canner lid. Wait 5 minutes, then remove jars, cool, and store.