Mix together the honey, red pepper flakes, sesame oil and olive oil in a small bowl. Put the sweet potato slices and sugar snap peas in a large bowl and toss them with half of the honey dressing until they are evenly coated. Season to taste with salt and pepper.
Transfer the vegetables to a baking sheet, arranging them so the potatoes are in a single layer. Cook under a preheated hot grill for 8 minutes, turning occasionally, until the potatoes are soft and turning golden.
When they are cool enough to handle, arrange the potato slices and peas over one of the potato cakes and crumble the blue cheese over the top.
Top with the remaining potato cake to create a sandwich and toast in a sandwich grill for 3–4 minutes or according to the manufacturer's instructions until the potato cake is golden and the cheese is just melting. Cut in half and serve immediately with a small bowl of the remaining honey dressing to drizzle if liked.