1. Heat a large pot, over medium heat, and once hot add in butter.
2. Once the butter has melted, add in onions, carrots, celery, and garlic to the pot and cook for 5 to 10 minutes, stirring occasionally.
3. After that time, add in broth, split peas, salt, and pepper to the pot, stirring to combine, and then bring to a boil.
4. Once boiling, reduce the heat to low, and let the pot simmer for about 2½ hours, until the split peas are tender.
5. After that time, puree the soup with an immersion blender or transfer it to a standing blender.
6. Once the soup is blended, serve, garnish with parsley, serve, and enjoy!
