Prep your onion by cutting it into ⅛ths, cutting through the root of the onion. This way the root will hold the onion together a bit. Set Aside.
Cube the pork shoulder into chunks around 2-3" cubed. The more similar in size, the more evenly they will cook.
Season the first batch (6-7 pieces) of pork liberally with kosher salt and fresh ground pepper.
Put your dutch oven on high heat. Add olive oil to coat the bottom.
We will only be adding small batches of the pork to the pan at a time. If we overcrowd the pan we won't get the brown crust we are looking for.
Add pork to the pan and DON'T move it around. Let it sit for 3-4 minutes or until it releases from the pan by itself and has a nice golden brown color.
Flip each piece, but don't stir/move them all around. Just a simple turn over.
Once they have browned on the second side, remove and set aside.
Repeat this process until all your pork has been browned.
Once all your pork has finished browning, return it back to the dutch oven with the red onions.
Add orange juice, chicken stock, cumin, oregano, and bay leaves. Mix until distributed.
Bring to a simmer and then cover with the lid. (I like to put foil on my lid so it doesn't get as dirty).
Move to 350-degree oven for 3-4 hours or until fork tender.
Once fork tender, remove the pork and put it into a deep-sided pyrex style dish, and cover to keep warm.
Take the remaining liquid in the pot and put it back on the stove to reduce it by about 75% or as much as you can without burning.
Once thick, pour that delicious liquid back over the pork. Mixing together and breaking the pork into smaller pieces at the same time.
Turn the oven on broil, and put the pork mixture back in the oven for just a minute or two. DO NOT TAKE YOUR EYES OFF IT. It will go from perfect to burnt in less than 1 minute. Note: this whole step is optional if it seems scary.
Enjoy with corn tortilla, avocado, and anything else that makes your soul happy.
Video
Notes
This can be crockpot friendly but only to a certain point. I 100% recommend still browning the pork in a pan, and then deglazing the pan (adding some chicken stock to get all the brown bits off the bottom). Reducing the liquid at the end is still an option, but you'd need to transfer that liquid back into a pot on the stove.
If you don't have a dutch oven, I would recommend looking into one. You do NOT need to spend $300+ on a Le Creuset. I have a link to a dutch oven that's under $50 here.
You don't have to broil the reduced liquid if you don't have time or are nervous, but it browns the remaining sugars in the sauce and gives it a little crispy texture at the same time. I recommend trying it at least once.
Don't snack on the pork the whole time the sauce is reducing. It's a rookie mistake and you won't be hungry for dinner. I have learned this lesson many many times.