Wash jars, keep them hot in simmering water.

In a large pot, combine strawberries, lemon juice, vanilla, and pectin mixed with ¼ cup sugar.

Bring to a full rolling boil over high heat, stirring constantly.

Stir in remaining sugar. Return to a rolling boil; boil hard for 1 minute.

Ladle into hot jars leaving ¼" headspace. Wipe rims, apply lids and rings fingertip tight.

Water bath for 10 minutes (Nebraska altitude — no adjustment needed).

Let sit 12-24 hours before moving. Label once sealed.