Cook the barley: First, rinse the barley and place it in a pot with about 3 cups of water. Bring it to a boil, reduce the heat, and simmer for 40–50 minutes until tender. Drain any excess water.
Boil the potatoes: While the barley cooks, peel and chop the potatoes. Boil them in salted water for about 20 minutes, or until they are soft. Drain and mash them with butter until smooth and creamy.
Combine the barley and potatoes: Once both the barley and potatoes are ready, mix them together in a large pot. If the mixture is too thick, feel free to add some warm water or milk until you get your desired consistency.
Cook the bacon and onions: In a pan, fry the bacon until crispy. Add the onions and cook them until golden brown and fragrant.
Serve: Spoon the mulgipuder onto plates, top with the crispy bacon and onions, and add a dollop of sour cream or a sprinkle of fresh herbs if you like.