Asparagus Cheese Puffs

Ingredients

• 1/2 pound asparagus, ends trimmed
• 3/4 cup whole milk
• 5 tablespoons unsalted butter, cut into 10 pieces
• 1/2 teaspoon salt, plus more for the pot
• 3/4 cup all-purpose flour
• 1/4 teaspoon cayenne pepper
• 3 large eggs, at room temperature
• 1 cup coarsely grated dry sheep's milk cheese, such as pecorino or Manchego
• 1/2 cup finely grated Parmigiano-Reggiano cheese