For the breadcrumbs, heat EVOO and butter over medium heat, melting butter into oil. Add garlic and stir 1-2 minutes. Add breadcrumbs and stir until very fragrant and deeply golden in color. Remove breadcrumbs from heat and cool; toss with parsley and cheese.
For the sauce, heat EVOO, a couple of turns of the pan, over medium-high heat in a Dutch oven. Add pancetta, guanciale or bacon and stir until rendered and crispy, 3-4 minutes. Add onions, garlic, rosemary, thyme, red pepper flakes and raisins, and stir to soften 3-5 minutes. Add white wine and stock, set cauliflower into pot, season with salt and pepper, and cover. Cook 15-20 minutes until very tender then mash up into small pieces with wooden spoon or potato masher.
Meanwhile, bring a large pot of water to boil for pasta. Salt water and cook pasta to al dente. Add a cup of starchy water from pasta to sauce just before draining.
Along with starchy water, stir butter into cauliflower sauce. Combine with pasta and adjust seasoning. Serve in shallow bowls topped with garlic breadcrumbs.