1. Make the cheddar frico: In a medium bowl, toss together cheese and flour.
2. Heat a large nonstick skillet over medium-low heat. Sprinkle about 1 1/2 tablespoons cheese mixture into skillet to form a 4-inch round.
3. Cook until cheese is starting to melt and become firm, 1 1/2 to 2 minutes. Using a small offset spatula, turn; continue cooking until it is firm and slightly golden, 15 to 30 seconds more.
4. Immediately drape frico over a rolling pin, and let cool slightly to set the shape. Repeat with remaining cheese mixture. If skillet gets too hot and frico begin to color too quickly, remove from heat for several minutes before proceeding.
5. Make the vinaigrette: In a small bowl, whisk together vinegar and mustard; season with salt and pepper. Whisking constantly, slowly add pumpkin-seed oil and then olive oil in a steady stream until thick and emulsified.
6. Slice apples and radishes on the thinnest setting of a mandoline or with a sharp knife. Place in a serving bowl; add mixed greens, and toss to combine.
7. Drizzle vinaigrette over salad mixture, and toss well to coat evenly. Serve immediately with cheddar frico.

Serves 10-12.