Bring a large pot of salted water to a rolling boil—this takes approximately 8-10 minutes. The water should taste like seawater; adequate salting prevents bland pasta that no sauce can rescue. Add spaghetti and cook to al dente (approximately 9-10 minutes), stirring occasionally to prevent sticking. Reserve 1 cup pasta water before draining, as the starch thickens your sauce.

While pasta cooks, heat extra virgin olive oil in a large skillet over medium heat until shimmering. Add minced garlic and toast for exactly 2-3 minutes until fragrant but not brown—burnt garlic tastes bitter and ruins everything. Stir constantly to ensure even cooking. Add freshly cracked black pepper and red pepper flakes, stirring for 30 seconds to bloom the spices.

The savory garlicky cacio e pepe recipe comes together now through careful emulsification. Remove the skillet from heat and whisk together Pecorino Romano, Parmesan, nutmeg, and 2 tablespoons reserved pasta water until smooth. The mixture should resemble thick wet sand. This prevents clumping when hot pasta enters.

Add hot drained spaghetti directly to the cheese mixture and toss vigorously for 1-2 minutes, adding pasta water one tablespoon at a time if the sauce seems thick. The starch and heat create an emulsion; toss constantly to prevent the cheese from seizing into clumps. This step requires attention and speed.

Remove from heat and stir in butter and kosher salt, tasting for seasoning adjustments. If the pasta pasta seems too dry, add additional reserved water gradually—the sauce should cling to strands without pooling at the bottom. Plate immediately into warm bowls to prevent cooling and thickening.

Garnish with fresh parsley and additional cracked pepper to taste. Serve immediately, as this elegant Italian pasta loses its silky texture within minutes as it cools.