In a medium saucepan, heat the vegetable oil over low-medium heat. Once hot, add the annatto seeds and fry for about 2 minutes, or until the oil has turned red. Strain the seeds and discard, keeping the oil. Add the oil back to the saucepan.
Slice very finely the lemongrass stalks (only the white parts, discard the greens), chilis, shallots, and garlic. To save time, you can process everything in a food processor until finely minced. Add the minced aromatics to the saucepan and fry for about 2 minutes. You don't want to fry too long or the aromatics might burn, so keep an eye on it.
Remove from heat, add the ground chili, salt, and maple syrup, and stir to combine. Let it cool completely at room temperature before transferring to a clean jar.
Store in the refrigerator for up to 3 weeks. Use in soups, marinades, stir-fries, noodles, etc. Make sure to give it a good stir before using.