Roast poblano peppers over an open flame. Carefully turning with tongs until their skin is completely charred. Place in a plastic bag, seal and steam for 10 minutes. Remove poblano peppers from bag and peel charred skin with fingers or by rubbing with a paper towel. Remove tops, veins and seeds. Set aside.

Add garlic, onion, cream cheese, cilantro, milk, salt and Poblano peppers in a blender container.  Blend until smooth.

Heat oil in a sauté pan over medium low medium heat.  Add creamy poblano mixture and simmer for 10 minutes; stirring every 3-4 minutes.

While Poblano mixture cooks, prepare spaghetti according to package instructions.  Drain and transfer pasta into Poblano mixture, carefully folding into sauce until completely covered.  Remove from heat and serve.  Garnish with cotija cheese and pieces of cilantro sprigs.