Place bacon in a large soup pot over a medium high heat.
When the bacon is brown and crispy drain away the fat, leaving about 2 tbsp in the pot.
Add onion, carrots, celery and garlic to the pot and sauté for a few minutes.
Add the dried peas, stock, bay leaves, rosemary and salt and pepper.
Bring to a simmer and continue cooking until the soup is thick and the peas are completely soft.
Stir in frozen peas and stir to heat through.
Stir in the vinegar and add salt and pepper to taste.