Bring a large pot of water to a boil, salt it, add the pasta and cook to al dente. Drain, reserving 1/2 cup of the pasta cooking water.
While the pasta is working, in a large, deep skillet or a dutch oven fitted with a lid, heat the EVOO, 2 turns of the pan, over medium-high heat. Stir in the onion and garlic for 2 or 3 minutes. Add the raisins and lemon zest and cook for a few minutes more. Stir in the stock and saffron and bring to a simmer.
In a large pot of boiling, salted water, cook the cauliflower until tender, 12 to 15 minutes. Drain and coarsely mash with a wooden spoon or potato masher. Stir in the butter to melt, then add the pasta and reserved pasta water; toss to combine. Add in the cheese as you toss.
Serve the penne in shallow bowls. Top with the almonds, basil and parsley.