In my way of thinking, there are three ways to turn out pork carnitas.
First, there’s the professional version, made in places (often taquerias) devoted almost exclusively to carnitas, and this is the standard bearer. Cooks break down whole pigs into their primal cuts and lower them into copper cauldrons of very hot lard where they crackle and bubble and fry as the temperature of the lard drops to a gentle roil in which the meat coasts to a golden tenderness over the next several hours. That method is hard to replicate at home (huge caldron of lard, primal cuts of pork, intimate knowledge of perfect temperatures), but it is the one that turns out classic carnitas texture and flavor.
The second way—the method I call “home-style”—is really easy, utilizing slabs of bone-in pork shoulder (or country ribs) cooked at a moderate temperature in a closed moist environment until nearly tender, then uncovered and roasted in a hot oven until all the liquid evaporates and the meat browns delectably in its own rendered fat.
The third—and I’ll admit that this isn’t a common approach—transforms the first method into something doable at home. Like the second approach, the meat is pork shoulder (or country ribs). But like the first, it’s cooked in lard, giving it that incredible texture only achieved by cooking meat submerged in its own fat. But the lard isn’t frying-temperature hot as at the beginning of classic carnitas preparation. Instead, just as if I were making traditional French duck confit, I cook the pork slowly in its fat until tender, then brown it when I’m ready to serve. This technique is very useful in a restaurant kitchen where heating/browning individual portions is necessary. This method takes longer (though you’re not really tending it), but the outcome is worth it.