Marinate beef in soy sauce, vinegar, garlic, and black peppercorns overnight.
Take them out of the marinade, pat dry, and season lightly with salt.
Pour about 1/4 cup of the coconut milk into a pan and heat until the oils and curd split.
Allow the curds to toast a bit and set aside.
Sear the beef in the remaining oil.
Add in the marinade, beef stock, and bring to a boil.
Transfer to the slow cooker, adding in the remaining coconut milk, bay leaves, jalapenos, and beef.
Cook on low for 8 hours.