In a large heavy-bottomed Dutch oven or deep skillet, heat extra virgin olive oil over medium heat. Add minced garlic and red pepper flakes; sauté for 60 seconds until fragrant without letting the garlic brown.

Pour in the dry rigatoni, low-sodium broth, and heavy cream. Stir well to submerge pasta. Bring to a gentle boil, then reduce heat to medium-low. Simmer uncovered for 11 to 13 minutes, stirring frequently so the pasta cooks evenly and starches naturally thicken the liquid into a silky sauce.

Remove the skillet from direct heat. Immediately fold in the whole-milk ricotta cheese, freshly grated Parmigiano-Reggiano, lemon zest, and freshly squeezed lemon juice. Stir gently until the cheeses melt into a velvety emulsion coating every rigatoni tube.

Add the fresh baby spinach to the hot skillet. Cover with a lid for 1 minute to let the spinach wilt gently in the residual steam, then stir through. Season with kosher salt and cracked black pepper to taste.

Ladle into wide shallow pasta bowls. Crown each serving with a rustic dollop of fresh ricotta, extra lemon zest spirals, shaved Parmigiano-Reggiano, and fresh micro basil sprigs. Serve immediately with warm crusty garlic sourdough.