In a 1 pint mason jar add in the red onions and thyme tightly. Place the jar in the sink so that if you spill the brine later it is okay.
Combine the water, vinegars, honey, salt and peppercorns in a small saucepan. Bring the mixture up to a simmer and stir to dissolve the salt. Carefully pour the mixture into the jar. I had the perfect amount.
Press the onions down with a fork genty to release any air bubbles. You may need to run it around the sides too. Let them cool for 20-30 min. Serve immediately if needed or they keep well refrigerated for 2-3 weeks covered.
Nutrition calculation is an estimation only. If you need nutritional calculations for medical reasons, please use a source that you trust.