Heat a dry skillet over medium-high. Roast peppers until blackened and blistered on all sides, turning frequently. Transfer to a covered bowl and let steam for 30 minutes. This makes the skins easy to peel.

Add potatoes to a saucepan and cover with water. Bring to a boil and cook until fork-tender, about 40 minutes. Drain and let cool.

Blend tomatoes, onion, garlic, tomato sauce, bouillon, cumin, oregano, and water until smooth. Heat oil in a saucepan, pour in the salsa, and simmer 10–15 minutes until thickened. Keep warm.

Peel potatoes while still warm and mash with butter, garlic salt, pepper, and sour cream. Blend in shredded cheese until melted and creamy. Set aside.

Carefully peel poblano skins. Slice a vertical slit, remove seeds gently. Stuff each pepper with potato-cheese mixture, leaving room to seal the top.

In one bowl, whisk flour, garlic powder, onion powder, and salt. In another bowl, beat egg whites to stiff peaks, then gently fold in yolks until light and airy.

Heat 1 inch of oil in a skillet to medium-high. Dredge stuffed peppers in flour mixture, then dip into egg batter. Fry in batches for ~2 minutes per side until golden and crisp. Drain on paper towels.

Plate the peppers and ladle warm salsa roja over them. Serve hot to maintain crispness.