If you'd like to try this recipe and you live in the US, Philadelphia Cream Cheese might do the trick. If you go to Brazil, I suggest you buy a couple in the supermarket the day you leave. It's pasteurized, etc. Peel, devein and wash shrimp, sprinkle with lime juice and salt. Leave in refrigerator until ready to use.
Chop tomatoes into big chunks and puree in blender.
Saute onion in olive oil until limp, add shrimp, cover and bring to a simmer. Add tomatoes, parsley, green onions and whole peppercorns. Simmer for fifteen minutes. Dissolve corn starch in milk. Add hearts of palm and milk to shrimp, stir for a couple of minutes and remove from heat.