Bring a large pot of water to a boil. Salt the water, add florets and cook 5-6 minutes. Remove florets with a slotted spoon or spider to drain. Reserve the cooking water for the pasta.
Heat a deep skillet over medium heat, add the butter and melt. When butter foams, add garlic and shallots, and season with salt and white pepper. Stir a couple of minutes and add wine or stock. Reduce by half, add milk or half-and-half, and reduce by half. Stir the gorgonzola into sauce and add sage; reduce heat to low.
Cook pasta in cauliflower cooking water to al dente. Reserve half a cup of starchy water and add to the sauce. Drain pasta and toss with florets and sauce. Top with grated or shaved Parmigiano-Reggiano cheese and serve.