These hollow, cheesy puffs taste best fresh from the oven, but they can be made ahead and reheated. Chef Kieron Hales of Cornman Farms in southeast Michigan serves them with predinner drinks.
Preheat oven to 400°. Line a baking sheet with parchment paper or a silicone baking mat; set aside.
In a medium saucepan, combine the water, butter and Worcestershire sauce. Bring to a simmer. Stir in mustard and turmeric; return to a simmer. Add flour all at once; mix vigorously with a wooden spoon until you can no longer see any flour specks and the mixture forms a ball. Remove from heat. Let stand 10 minutes.
Beat in one egg at a time, mixing vigorously until smooth. (The first egg should be fully incorporated before adding the second.) Fold in cheese and oregano.
Scoop dough onto prepared baking sheet in approximately 1-inch spoonfuls at least 1 inch apart. Bake 5 minutes. Rotate pan and reduce oven to 350°F. Bake until puffed, golden brown and dry to the touch (the cheese may still be bubbling a bit), about 30 minutes. They should feel light and hollow when picked up.
Transfer to a cooling rack. Serve warm or at room temperature. Store in an airtight container in the refrigerator up to 1 week or freeze up to 3 months; re-crisp in a warm oven before serving.