Step 1

Combine the green beans, yellow wax beans, kidney beans, onion and parsley in a mixing bowl, tossing to incorporate.

Step 2

Whisk together the oil, sugar, vinegar, salt and pepper and the thyme leaves in a liquid measuring cup. Pour over the bean mixture and stir to coat evenly.

Step 3

Cover with plastic wrap and refrigerate for at least 6 hours, and up to 3 days.