Pasta with Asparagus and Lemon Sauce

Ingredients (12 items)

You have this You need this

• 2 lemons
• 1 (16 ounce) box penne pasta
• 5 tablespoons butter, divided
• ¾ pound asparagus, trimmed and cut into 1-inch pieces
• salt and freshly ground black pepper to taste
• 3 tablespoons all-purpose flour
• ¾ cup heavy cream
• 1 ½ cups vegetable broth, or more to taste
• 4 sprigs fresh parsley, chopped
• 1 pinch white sugar, or to taste
• 2 ripe tomatoes, seeded and diced
• ½ cup freshly shaved Parmesan cheese