Heat olive oil in a large Dutch oven or soup pot over medium heat.
Add onion, carrots, and celery. Cook until vegetables start to soften, about 5-7 minutes.
Stir in garlic, thyme, rosemary, and red pepper flakes. Cook for 1 more minute until fragrant.
Add bay leaf, ham hock (or diced ham), split peas, and chicken broth.
Bring to a boil, then reduce heat to low. Cover partially and simmer for 60-75 minutes, stirring occasionally.
Remove ham hock. Shred the meat and return it to the pot (if using diced ham, skip this step).
Discard bay leaf. Adjust seasoning with salt and pepper to taste.
Serve hot with crusty bread for a comforting meal.