1 pound cauliflower rice
4 ounces shiitake mushrooms, roughly minced in a food processor
8 ounces button mushrooms, roughly minced in a food processor
½ cup extra-virgin olive oil, divided
2 tablespoons unsalted butter
1 large onion, finely diced (about 2 cups)
6 garlic cloves, thinly sliced
½ teaspoon crushed red pepper flakes
3 tablespoons miso paste
1 tablespoon rosemary, minced
¼ cup double‑concentrated tomato paste
1 cup Parmesan, grated
3 tablespoons parsley, chopped
1 lemon, zested
1 pound rigatoni
Salt and pepper, to taste