Prepare your boiling water canner. Heat four half pint jars in simmering water until ready to use, but do not boil. Wash lids in warm soapy water and set aside with bands.
Puree the strawberries in a food processor until smooth.
Combine the strawberry puree with the sugar, honey, lemon juice, vanilla extract, and salt in a deep pot set over medium heat. Bring the mixture to a boil, stirring frequently to prevent scorching.
Lower the heat and simmer until the mixture is very thick, about 60-90 minutes, stirring frequently. Any foam produced by the strawberries will disappear with the cooking process. The strawberry honey butter is finished cooking when it holds shape on a spoon.
Using a jar lifter, grab one canning jar, place on a towel or wooden cutting board, then ladle hot butter into a hot jar leaving a 1/4 inch headspace. Remove air bubbles (this headspace tool is perfect for this). Wipe jar rim.
Center lid on jar and apply band, adjust to fingertip tight. Place jar in boiling water canner. Repeat until all jars are filled.
Once the water is boiling, process the jars for 10 minutes, adjusting for altitude. Turn off the heat, remove lid, and let jars stand in the water for 5 minutes. Remove the jars and let them cool undisturbed for 12-24 hours. Check lids for seal, they should not flex when the center is pressed.