Bun bo Hue (spicy beef noodle soup)

My favorite Vietnamese food is probably bun bo Hue, a spicy beef noodle soup that I find much more comforting than pho. However, it's also less popular and therefore harder to find a good bowl outside of Little Saigon (or my mother's kitchen). I never even dreamed of making it until my mom found a bun bo paste at a Vietnamese grocery store , so we tried using it and adding some extra spices. The result was very good, what my mom described as "80% the real thing." Enjoy!

Ingredients:
1 tray beef shank (2 lean slices)
1 pork hock
4 cups of water
4 tablespoons of bun bo paste
1 lemongrass stalk
2 tablespoons fish sauce
1 tablespoon salt
1 white onion
1 package of rice vermicelli, prepared according to package instructions
sliced green onion, cilantro, mint, lime wedges, thai chile for garnish

Directions:
1. Salt the beef shank and pork hock, then simmer in 4 cups of water for about 1 hour.

2. Remove meat and slice around bone. You can discard the bone or save it for when you add everything back into the pot.

3. Skim the fat off the top of the broth. If you have the time, you can put the pot in the refrigerator overnight so the fat rises to the top and solidifies, then just remove it with a spoon. Re-heat the broth by simmering if you do this.

4. Bruise the lemongrass stalk or slice in half lengthwise and add to broth.

5. Mix the paste/soup base with the cooked meat and add back to the pot along with fish sauce.

6. Simmer for about 1 hour. Serve with rice vermicelli topped with garnishes to taste.

I'd like to try this in a slow cooker but I haven't figured out the conversions yet. My mom's guess was to use 4 cups of boiling water and pour it over the meat in the slow cooker, then cook on low for about 2 hours.
Also, nutritional info to follow if I can find it.