Step 1

Remove the stems from one large bunch of Swiss chard and chop into 1/4 inch pieces. Finally dice a little bit of red onion.

Step 2

Put the chard stems and onion in a bowl and sprinkle with the salt. Set aside while you make the pickling brine.

Step 3

Heat a saucepan over medium heat for a few minutes. Then add the mustard seeds and let them toast for 2 minutes or so to release the flavor.

Step 4

Add the two types of vinegar, water, sugar and peppercorns. Bring to boiling and stir until the sugar has dissolved, then remove from the heat.

Step 5

Place the chard stems and onion in a pint mason jar, packing the vegetables tightly. Pour the warm brine over the rainbow chard stems and cap the jar.

Step 6

Let the jar cool at room temperature for an hour or so, then put it in the refrigerator. The pickles will be ready in a day, and will last in the refrigerator for about 3 weeks.