Authentic Slow-Braised Carnitas

1 orange, halved

1 lime, halved

1 yellow onion, quartered

6 garlic, smashed

2 kg pork shoulder, cut into 5 cm chunks

30 ml chipotle in adobo, minced

500 ml chicken stock

30 ml vegetable oil

16 corn tortillas, warmed

15 ml kosher salt

10 ml cumin

10 ml dried oregano

5 ml black pepper, freshly ground

2 bay leaf