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If you're going to pay that much for butter, instead of shipping from Ireland, why not go Portland local:
Jacob's Creamery has grass-fed Jersey cow butter, which you can buy in Shemanski Park and other local markets: jacobscreamery.com
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Jacobs Creamery-Handcrafted Artisan Cheeses
Failing that, yes, Trader Joe's is probably the place to go.
5'0" female, 45 years old. Started Primal October 31, 2011, at a skinny fat 111.5 lbs. Low weight: 99.5 lb on a fast. Gained back to 115(!) on SAD chocolate, potato chips, and stress. Currently 111.