Soak the bihon rice noodles in a baking dish filled with water for 10 minutes to soften. Set aside.
In a large sauté pan or skillet, add olive oil over medium heat. Brown the pork for 2-3 minutes on each side. Cover the pan to finish cooking the inside for another 2 minutes or until cooked. Remove the pork from the pan and set aside.
Add the sliced Chinese sausage to the pan and cook for 5 minutes. Remove the sausage once cooked and set aside.
Toss the diced onion, minced garlic, shredded carrots, and diced celery in the pan. Sauté for 3 minutes until softened. Once softened, add the shredded cabbage.
Add the oyster sauce, chili sesame oil, chicken broth, soy sauce, and juice of 1 lemon to the pan with the vegetables. Stir to combine. Cover over low heat and simmer for 5 minutes. Optional: If using the achuete annatto powder, stir the powder into the liquid to dissolve.
Remove the noodles from the water and place in the pan. Add the pork and Chinese sausage. Stir the noodles until the liquid is mostly absorbed. Season with salt and pepper to taste and additional lemon juice to preference. Garnish with hard-boiled egg slices. Enjoy!