Step 1Roast the chiles over a gas flame on the stove top until they are blistered. Place in a plastic bag and let stand 10 minutes. Peel the chiles, remove the stems and seeds and wash. Place the chiles in a blender, add the almonds and the chicken broth and blend until pureed. Set aside.
Step 2Melt the butter in a large saucepan. Add the carrots, celery and onion and cook for 5 minutes to soften the vegetables. Gradually stir in the flour, and continue to stir about 2 to 3 minutes to lightly brown the flour coating the vegetables. Slowly pour in the milk, stirring as it comes to a boil. Turn down the heat and simmer for five minutes to blend the flavors. Strain and discard the vegetables.
Step 3Combine the chile and milk mixtures in a large saucepan. Add the bouillon and stir to combine. Bring the mixture to a boil, stirring constantly, until thickened, 2 to 3 minutes. Check for seasoning and add more salt if desired.
Step 4Ladle the soup into broad, shallow soup bowls. Add two shrimp to each bowl and garnish with a few slivered almonds.