1. Preheat your oven to 300°F or 150°C.

2. Heat two tablespoons of butter or oil in a large Dutch oven or heavy pot over medium-high heat. Add the wild boar cubes and sear them until browned on all sides; this should take approximately 5 minutes. Remove the browned meat from the pot and set it aside for the time being.

3. Add an extra tablespoon of butter or oil to the pot, followed by the chopped onion. Cook until the onion has softened and turned a light shade of brown, which should take about 8 minutes.

4. Next, add the minced garlic, thyme, and rosemary to the pot. Cook for 1 minute, constantly stirring the mixture to prevent burning.

5. Add the red wine to the pot, scraping the bottom to release any browned bits that have accumulated. Bring the wine to a boil, then reduce the heat to a low simmer for 5 minutes.

6. Now add the beef broth, tomato paste, and browned wild boar back into the pot. Stir until everything is well combined, then cover the pot with a lid and transfer it to the preheated oven.

7. Let the stew braise in the oven for 2 1/2 to 3 hours, or until the meat has reached a tender state and falls apart easily.

8. Serve the stew hot, with a garnish of fresh thyme or rosemary, if desired. Consider serving oven-baked potato wedges or mashed potatoes on the side to complement the dish.