1/2 teaspoon (2.5 milliliters) salt, plus more for seasoning inside loin
1/2 teaspoon (2.5 milliliters) pepper, plus more for seasoning inside loin
1 1/2 cups (360 milliliters) beef stock
Butterfly the wild boar loin.
Put slices of garlic and rosemary sprigs in the center of the loin, then season with salt and pepper. Roll up the loin and tie it with kitchen string.
In a large pan, melt butter with olive oil. Add boar and sear on all sides. Remove from pan. Add onion and apple and fry until soft. Add loin back to pan.
Pour the red wine over the loin. Reduce for two minutes, then add stock. Add salt and pepper. Cover the pan and let cook. When the boar has cooked through, remove the lid, take out the boar and cover with an aluminum foil tent. Let the sauce reduce.
Slice boar into medallions. Remove string. Pour sauce over top, then garnish with arugula and olive oil.