Preparation / Directions:
Prepare grill: If using charcoal, allow coals to burn to medium-low heat or use indirect grilling method. If using gas, use low setting.
In a small bowl, whisk together vinegars, garlic salt, shallots, olive oil and pepper.
Wipe mushrooms with a damp paper towel. Brush both sides with vinaigrette. Place rounded-side down on grill Cook 2 to 3 minutes. Lift with tongs and rotate 1/4 turn Grill 1 to 2 minutes longer. Watch carefully to prevent burning. Turn mushrooms and brush lightly with vinaigrette.
Grill 2 to 4 minutes.
Place mushrooms on cutting board and drizzle with a little more vinaigrette; allow to rest for 10 minutes. Slice on the diagonal. Taste and season with salt and pepper if needed.
Toss salad greens with enough vinaigrette to barely coat leaves. Refrigerate leftover vinaigrette; it will keep up to 2 weeks in the refrigerator.
Divide greens among 6 plates. Alternate slices of mushrooms with slices of cantaloupe. Sprinkle with feta cheese.