Heat olive oil in large saucepan over medium heat. Add onion, poblano pepper, oregano, cumin and cinnamon and cook for about 10 minutes or until onion is tender, stirring occasionally.
With about 1 minute left, add garlic and combine. Mix in chili powder and flour and stir for about 2 minutes until combined. Gradually add chicken stock, whisking constantly and scraping up bits on bottom of pan. Bring to boil and simmer for about 5 minutes.
Remove from heat and use immersion blender to puree until smooth.
Return saucepan to medium-high heat and stir in the chocolate, almond butter, tomato paste and salt. Simmer for 5 minutes or until sauce has thickened. Adjust for salt if needed. Serve warm.
Notes
Check your spices and make sure they aren't expired. In order to have great flavor, you want to make sure your spices aren't too old.
Use quality dark chocolate for the sauce. If you can find Mexican chocolate, even better.
If using a blender, blend the sauce in batches and cover the top with a towel so it doesn't go everywhere.
The sauce can be stored in an airtight container in the fridge for 3-4 days or in the freezer for 3 months.