Bring 6 quarts water to boil and add 2 tablespoons salt.
In a 12- to 14-inch saute pan, heat olive oil until smoking. Add garlic and fennel and cook, stirring frequently, until light golden brown and quite soft, about 10 minutes. Add 1 cup bread crumbs and crushed red pepper flakes and continue cooking 4 to 5 minutes.
Cook pasta according to package instructions until just al dente and drain well. Pour hot pasta into pan, add mint and toss to mix well. Pour into warm serving dish, sprinkle with remaining breadcrumbs and fennel tops. Drizzle with extra virgin olive oil and serve.