1 1/4 cups pitted brine-cured green olives
1/2 cup chopped fresh flat-leaf parsley
1/2 cup olive oil
1 (2 1/2-lb) cauliflower head, cut into 1-inch wide florets (about 8 cups)
3 garlic cloves, finely chopped
Scant 1/2 teaspoon dried red-pepper flakes
1/4 cup water
3/4 pound dried spaghetti or long straight pasta
1 oz finely grated Parmigiano-Reggiano (about 1/2 cup) plus more for serving
3/4 cup whole almonds with skin (3 3/4 oz), toasted and coarsely chopped