Melt the butter in a square baking dish (either 8-inch x 8-inch or 9-inch by 9-inch). Add the grapes and walnut to the dish and toss in the butter until coated. Sprinkle grapes and nuts with sugar and stir to distribute sugar.
Bake for 15 to 17 mins, stirring once, or until the grapes are tender and almost bursting.
Remove from oven and set aside.
Toasts:
Place baguette slices on a Sil-Pat lined baking sheet. Brush or drizzle with olive oil.
Turn oven to broil, and toast bread slices for 2 to 3 minutes (watch them carefully so they don't burn!) until golden brown.
Remove from the oven and set aside.
Bleu Cheese Spread:
Add cream cheese, bleu cheese, vinegar, and olive oil to a food processor. Blend until smooth. Add milk, 1 teaspoon at a time, until desired consistency is reached. (You want a frosting texture.)
Assembly:
Spread 1 to 2 teaspoons bleu cheese spread on each toast.
Using a slotted spoon, top bleu cheese spread with grapes and walnuts.
If desired drizzle with the pan's juices from roasting the grapes or a little honey.
Notes
If you have a really pungent bleu cheese I'd start with a light spread on the toasts. Unless you're super into bleu cheese, then choose your own level of cheese in your face. You could also choose a milk bleu cheese and use more spread per toast.