Preheat the oven to 450°. Heat 2 large roasting pans in the oven for 5 minutes. Meanwhile, in a large bowl, toss the zucchini with the olive oil and crushed red pepper; season generously with salt and pepper. Spread the zucchini on the hot pans and roast for 30 minutes without stirring, until the rounds are tender and their bottoms are golden. Transfer to a platter, garnish with the mint and serve.