Heat a grill pan or outdoor grill to medium high. Spread the corn with a thin layer of softened butter and place on grill, grill 15 minutes or until golden brown to edges of kernels. Cool to handle. Place a small bowl inverted in a large mixing bowl. Steady the cobs on the smaller bowl bottom and scrape the charred kernels into the larger bowl using a sharp knife. Puree half the corn in food processor with 1/2 cup stock.