Roll the goat cheese in the crushed pecans, gently pressing the pecans into the cheese so that it sticks. Wrap in plastic and freeze until firm, about 30-45 minutes. Remove from freezer and allow to sit at room temperature for 15 minutes. Unwrap and slice into rounds. It's ok if it crumbles a bit. Allow the cheese rounds to sit at room temperature while you prepare the grape compote.
To make the compote, bring grapes, butter and sugar to a boil in a small saucepan. Reduce heat to medium and cook, stirring often, until sugar dissolves and mixture thickens. Using a wooden spoon, break up some of the grapes. Stir in the honey, rosemary and cornstarch and continue to cook until syrupy, mashing the grapes with a spoon. Remove from heat and allow to cool. Mixture will continue to thicken as it cools.
Slice the crusts off of the bread and cut each slice into quarters. Toast. Top each toast square with goat cheese and drizzle with grape compote. Garnish with additional rosemary, if desired.