Smash the garlic cloves with the flat of your knife and drag it on the cutting board. Set aside.

In a large jar with a tight-fitting lid (four-cup capacity), add the red wine vinegar, honey, kosher salt, smashed garlic, and fresh thyme. Close the jar and shake until all ingredients are thoroughly combined.

Peel the onion and slice it as thinly as possible in rounds. It’s okay if you need to turn the end of the onion on its side to cut more thin slices. Perfection is not needed.

Put the sliced onions in the jar, seal the lid very tightly, and shake the jar vigorously for 10 seconds.

Leave the jar on the counter and shake every 10-15 minutes, until the onions have reduced and have sunk completely into the liquid.

At this point you can serve the onions or store in the fridge for about one week.