Place guajillo chilies in a heat proof glass or bowl. Pour over boiling water until the chilies are submerged. Cover the bowl with a plastic bag and let sit for 15 minutes. This will rehydrate the peppers. Drain the peppers(place them in a strainer), open them up and remove the stems and most of the seeds. It's okay for some seeds to be left. You might want to wear gloves for this!

Heat up a small pan over medium heat and add the coriander seeds. Toast until fragrant, 3 minutes. Place them in a food processor fitted with the "S" blade attachment, and add the garlic. Pulse. Add the cleaned chili peppers, and pulse until a paste forms. (alternatively, you can grind the ingredients with a mortar and pestle, if you have one- this is the traditional way to do it).

Add the lemon juice, vinegar, paprika, salt, cumin, garlic powder, and cayenne pepper, and process for about a minute. The paste should still have texture but be on the smoother side. With the processor running on low, drizzle in 1/4 cup olive oil. Process until olive oil is incorporated.

Transfer the Harissa paste to a glass jar, cover the top with 2 Tbs olive oil, and close with an airtight lid. Store in the fridge.