1. Combine the garlic and the olive oil in a small saucepan. Heat gently until the garlic turns golden. Do not allow it to brown. Remove from the heat and set aside.
2. Meanwhile, remove the dark green leaves from the chicory and reserve them for another use. Tear the white and yellowish green inner leaves into bite-size portions and place in a salad bowl. Add the Gruyere cheese and toss to combine.
3. Brush the garlic-flavored oil over both sides of the bread slices, then slide them under the broiler. Cook, turning once, until both sides are nicely browned.
4. In a small bowl, whisk together the vinegar, mustard, salt, and cayenne. Whisk in the walnut oil. Scatter the parsley over the chicory and pour on the dressing. Toss to coat evenly.
5. Place a warm slice of bread on each salad plate. Divide the chicory mixture among the 4 plates, arranging it over the bread. Serve immediately.