Penne with Ricotta Cheese and Greens

INGREDIENTS

• Coarse kosher salt, to taste
• 1 bunch Tuscan kale or other hearty greens, thick stems trimmed, leaves cut crosswise into 2-inch pieces
• 6 to 8 oz. dried penne, preferably multigrain
• 2 Tbs. extra-virgin olive oil
• 2 tsp. minced fresh thyme
• 1 shallot, minced
• 1 tsp. grated lemon zest
• 1/2 cup grated Parmigiano-Reggiano cheese
• 1/2 cup fresh whole-milk ricotta cheese
• Freshly ground pepper, to taste