Preheat oven to 400 degrees F.
Place poblanos on a rimmed sheet pan and roast in oven for 25-30 minutes, until softened and charred on the outside, flipping once halfway through cooking time. Remove from oven, set aside & cool.
While poblanos are roasting, prepare the potato soup. Preheat soup pot over medium-high heat. Add 2 teaspoons olive oil.
Saute' onions until translucent, about 5 minutes.
Add cubed potatoes, broth, salt & pepper. Bring to a boil.
Reduce heat to a low boil and allow to cook until potatoes fall easily from a fork when pierced. Remove. Strain, reserving liquid.
Place potatoes in blender (or back in pot if using an immersion/stick blender)
Peel and puree roasted peppers, and add to potatoes.
Add 1 cup broth used in cooking to blender (or pot if using immersion/stick blender).
Process until smooth, then return to pot if using conventional blender. Add heavy cream.
Heat over medium heat until simmering.
Adjust seasoning to taste, stir in grated cheese until melted, and serve while hot.