Place the bread and evaporated milk in a bowl. Let sit for 15 minutes.
While the bread is sitting in the milk, poach the chicken breasts in the chicken stock for 15 minutes.
Remove the chicken breasts and let cool completely. Save the stock.
Heat up vegetable oil in a large sauce pan over medium high heat. Add in the onions and garlic. Sauté for 5 minutes.
Add in the aji amarillo paste. Cook for another 5 minutes.
While the onions and garlic are cooking, add the soaked bread slices, walnuts, and cheese to a food processor or blender.
Blend until smooth.
Add the sautéed onions and garlic to the food processor.
Blend until smooth.
In the same sauce pan, add in the shredded chicken, the spicy cream sauce, and 2 cups of the chicken stock. Simmer covered on medium heat for 15 minutes.
Stir in the potatoes. Cook for another 5 minutes uncovered.
Turn off the heat. Garnish with sliced hard boiled eggs.