See my reply here

Yeah it's always such a let down even from really amazing Viet restaurants. This dish always seem to be every restaurant's Achilles heel somehow

I absolutely suck at writing up recipes but the steps and list of ingredients here are similar to mine but I like it really bold so I double the amount of aromats especially lemongrass and spices. And instead of chuck I used shank and tendon for the super thick and rich consistency from all the gelatin in both cuts. If you do use tendon, just keep in mind that they take longer to soften than the shank so then the shank reach your desired softness, fish them out and continue to cook the tendon until they're 90% put in the carrots then when that's done add back the shank

It's also very popular with rice noodles in a diluted version as a soup but I prefer it with bread