What you will need:
1 cup cold water
6 tablespoons unsalted butter, cut into 6 pieces
1 cup unbleached all-purpose flour
Pinch kosher salt
4 large eggs, at room temperature
4 ounces prosciutto, thinly sliced and finely chopped
4 ounces (1 1/4 cups) finely grated Parmigiano-Reggiano cheese
2 teaspoons rosemary leaves, minced
2 teaspoons thyme leaves, minced
1 teaspoon freshly ground black pepper
Steps to yummy goodness:
1. Position racks in the top third and bottom third positions of the oven and crank up the heat to 425°F (218°C). Line 2 baking sheets with parchment paper or nonstick baking sheets.
2. Bring the water, butter, and salt to a boil in a medium saucepan over medium-high heat.
3. Dump the flour into the boiling butter mixture all at once and, using a wooden spoon and good old elbow grease, mix until the flour clumps into a ball and pulls away from the sides of the pan. Continue stirring over medium-high heat until the dough leaves an even, dry film on the bottom of the pan, 2 to 3 minutes.
4. Drop the dough into the bowl of a stand mixer fitted with the paddle attachment and mix on low speed until the dough is just barely warm to the touch, about 5 minutes.
5. Plop in an egg, increase the speed to medium, and beat until incorporated. The dough may look hopelessly soupy and broken at first, but fear not and continue mixing until the blob turns smooth and slick. Repeat with the rest of the eggs, adding them 1 at a time. Using a spoon, stir in the prosciutto, cheese, rosemary, thyme, and pepper.
6. Drop rounded tablespoons of the dough, or use a 1-tablespoon cookie scoop to make plump mounds, on the prepared baking sheets, spacing them about 2 inches apart. Have a glass of cold water handy and dip the spoon in it every so often to help make the dough easier to scoop.
7. Bake the puffs until golden brown, 20 to 25 minutes, reversing and rotating the sheets once halfway through baking.
8. Transfer the sheets to a wire rack to cool slightly. Then whip off your apron, pop as many puffs as can fit into your mouth, place the rest of the puffs on a platter, and offer them to your guests post haste.
You can bake these up to 2 hours in advance, then reheat them in a 350°F [176°C] oven for 5 to 7 minutes. Or freeze a batch of baked, cooled puffs for up to a month and, just before guests arrive, pop the frozen puffs into a 350°F [176°C] oven for 10 to 12 minutes.