In a saucepan over low heat, combine strawberries, sugar, and lemon juice.
Cook, stirring regularly until sugar is completely dissolved.
Bring mixture to a hard boil for about 8 to 10 minutes.
To test for setting, place a small saucer in the freezer for about 5 minutes. Spoon a small amount of jam on the cold plate, leave for about 30 seconds, and use the index finger to push in the jam. If it wrinkles and does not flood back to fill in the gap, it's ready.
With a spoon, remove any scum that floats on top. Or add butter to dissolve the scum.
Remove from heat and add pepper. Stir to combine.
Allow jam to settle for about 15 minutes and then transfer into clean, sterilized jars, leaving about ¼ inch headspace. Close the tight-fitting lid.