Roughly chop the strawberries in half. Place them in a large saucepan and add sugar. Stir to combine.
Place the saucepan over high heat and bring to a boil.
Cook, stirring often, until the berries soften and the liquid bubbles and thickens. Make sure you skim any foam that appears on the top.
Add the balsamic vinegar and stir well.
Keep the mixture on a slow boil until mixture reaches 220 degrees using a jam thermometer.
Add balsamic glaze and black pepper and stir through and cook for a further 2mins.
Remove from heat.
Place freshly washed and rinsed jars in the oven along with the lids and bring to 100C and remove from oven carefully.
Using a jam funnel if you have one, fill jars leaving 6mm space at the top edge.
Wipe the rims of the jars and place the lids on each jar, tightening until finger tight.
Fill a large clean saucepan with hot water and bring to the boil.
Place the jars standing up carefully into the saucepan, making sure the lids are covered with water.
Process jars in a boiling water bath for 10 minutes.
Remove jars carefully using a large scoop or jam tongs and place them on a tea towel to cool making sure to retighten lids.