To prepare nuts, place sugar in a small skillet over medium heat; cook 90 seconds or until sugar dissolves, stirring as needed so sugar dissolves evenly and doesn't burn. Reduce heat; stir in walnuts. Cook over low heat 30 seconds or until golden. Spread mixture onto foil coated with cooking spray. Cool completely; break into small pieces.
To prepare dressing, place cider in a small saucepan over medium-high heat; bring to a boil. Cook until reduced to 2 tablespoons (about 5 minutes). Combine water and cornstarch in a small bowl; add to pan. Bring cider mixture to a boil, stirring constantly; cook 30 seconds. Remove from heat. Stir in shallots, vinegar, salt, and pepper; let cool.
To prepare salad, place salad mix in a large bowl. Drizzle with dressing; toss gently to coat. Divide evenly among 4 plates; top with berries, cheese, and walnuts. Serve immediately.
Wine note: This market salad is a kaleidoscope of bold flavors and compelling textures, from the berries to the caramelized walnuts to the crumbled blue cheese. It needs a powerhouse of a wine to match it all: Walla Walla Village Gewürztraminer 2003 (Walla Walla, Washington; $16). It's sassy with bright tropical fruit flavors (a great counterpoint to the saltiness of the cheese), a citrusy edge, and loads of spice. -Karen MacNeil