In a large pot, sauté the garlic, onion and carrot in olive
oil over medium heat, stirring until soft – do not brown.
Add potatoes, water and broth, bring to a boil and then
simmer until potatoes are soft (10 – 15 minutes). While the
potatoes are simmering, cook linguica in a skillet over
medium to high heat, browning on both sides. Transfer to
paper towels to drain.

Transfer cooked potatoes to a blender using a slotted spoon, add 1 ½ cups cooking liquid and puree until smooth (hold cover tightly, covered with a kitchen towel). Return puree to the pot and add linguica and the red potatoes. Simmer,
covered for 10 – 15 minutes until potatoes are done. Correct seasoning with salt and pepper, being careful with the salt if salted broth was used.

Recipe by Charlie Burke

http://www.theheartofnewengland.com/food-PortugueseKalePotatoSoup.html