"Rachael Ray's Cacio e Pepe Mac 'n' Cheese with Chard"

Ingredients

• 2 tbsp. olive oil
• 1 small onion, finely chopped
• 2 large cloves garlic, chopped
• Salt About 1 tbsp. each black peppercorns and pink peppercorns, coarsely ground in a spice mill or crushed together in a mortar and pestle
• 1 bunch Swiss chard, center stems removed and leaves thinly sliced
• Freshly grated nutmeg (grate it while making one pass over the pan)
• 1 cup mascarpone cheese
• 1 cup fresh ricotta
• ½ cup each Parmigiano-Reggiano and Pecorino Romano
• 1 lb. fusilli lunghi (long corkscrew-shaped pasta) or fusilli