In a large pot or Dutch oven, melt the butter over medium heat until it begins to foam. Add onions, carrots, celery, ¼ teaspoon salt, and ½ teaspoon black pepper. Sauté for 5 to 8 minutes until the vegetables soften.

Stir in garlic and cook for another minute until fragrant. Add the split peas and stir to combine.

Add the bay leaf, 1 teaspoon of thyme, vegetable broth, and water. Bring to a boil, then reduce heat and simmer uncovered for 60 to 90 minutes, stirring occasionally.

As the soup thickens, stir more frequently to prevent sticking. If it becomes too thick, add a bit more broth or water.

During the last 15 minutes of cooking, stir in the diced turkey.

Once the peas are fully softened and the soup reaches your desired consistency, remove the bay leaf and stir in the remaining 1 teaspoon thyme. Adjust seasoning with more salt and pepper if needed.

Serve hot, topped with garlic croutons and extra black pepper if desired.