In a large skillet, heat oil over medium heat. Add onion to the skillet and sauté until the onion is translucent. Add the garlic and sauté for 30-45 seconds more.
Add the onion mixture, split peas, carrots, and celery to a 4-6 quart slow cooker. Pour in the vegetable broth then add soy sauce, salt, and pepper. Stir until combined then lay the bay leaf and thyme sprig on top.
Cover and cook on high 4-6 hours or 8-10 hours on low, stirring occasionally.
During the final hour of cooking, taste and add salt if needed.
Remove the bay leaf and thyme stem. Salt and pepper to taste and top with fresh parsley.
Notes
The soup will thicken as it cools.
For a thicker soup, blend 1-2 cups of the soup or use an immersion blender until the desired consistency is reached.
For a chunkier soup, reserve 1 cup of peas and add them halfway through cooking.
Serve topped with croutons or crackers, or side of toasted baguettes for dipping.
If you don’t have fresh thyme, you can use ½ teaspoon of dried thyme.
The leaves will fall off the fresh thyme as the soup cooks. Be sure to remove the stem when the soup is finished cooking.