1. Soak sundried tomatoes in boiling water for 30 minutes, until soft.
2. Heat oil in a small saucepan over medium heat, add onion and sauté for 3-4 minutes, or until translucent.
3. Add garlic and tomato paste, and cook for another 1-2 minutes.
4. In a blender or food processor, combine sundried tomatoes and their soaking liquid with the onion, garlic, tomato paste, and oil; purée until smooth.
5. Transfer the purée to a small saucepan and bring to a gentle simmer over medium heat.
6. Reduce heat to low, cover, and let simmer for 20 minutes, stirring occasionally.
7. Transfer to a small jar and let cool completely before refrigerating.

For the Meat

1. Chill the processor bowl, blade, and meat in the freezer for about 30 minutes before grinding.
2. Once ground, roll the ground meat mixture into walnut-sized balls.
3. Cook in a cast iron skillet over medium-high heat (approximately 375°F/190°C), shaking the pan to keep the balls rolling and evenly brown on all sides.
4. Cook for 7-9 minutes for a medium doneness, depending on the size of the balls.
5. Skewer each ball on a sprig of fresh rosemary and serve with homemade sundried tomato ketchup.