Heat vegetable oil in a sauté pan over medium-high heat and sauté the diced onions and minced garlic for about 5 minutes until softened.

Grind juniper berries and coriander seeds in a spice grinder, then add to the sauté mixture along with a bay leaf.

Stir in diced tomatoes, water, cider vinegar, honey, chili powder, and salt, cover and simmer on medium-low heat for 30 minutes.

Add grated chocolate into the sauce and continue to simmer for an additional 30 minutes.

Allow the sauce to cool slightly before puréeing with an immersion blender until smooth.

Preheat oven to 325°F (163°C). Pour ¾ of the sauce over the pork roast in a baking dish.

Bake the dish for 45 minutes, then baste with remaining sauce and bake for another 45 minutes.

Use a meat thermometer to check that the internal temperature reaches 150°F (65°C), then let it rest for 15 minutes before slicing.