Heat a skillet and add vegetable oil. Add chopped carrots, celery, and onion and cook until soft, about 6 minutes. Move softened vegetables to the sides of your skillet, leaving a space in the middle.
Add more cooking oil and cook the ground beef until browned, about 6-7 minutes. Mix beef and vegetables together, season with a pinch of salt and pepper, and cook for another minute.
Transfer vegetable and beef mix into the slow cooker. Add your broth, tomatoes, tomato paste, herbs, and the parmesan rind (optional).
Cover and cook on low for 6-8 hours or high on 4-6 hours. If you don't want the rosemary to overpower your dish, fish out sprigs around 2-3 hours in.
When finished cooking, remove bay leaves, thyme, and parmesan rind, and cook on high uncovered for 30 minutes.
Boil your pasta according to package directions and spoon bolognese sauce over the top. Add parmesan and garnish with fresh herbs to serve!
