Makes 2 dozen
1 cup milk
8 tablespoons unsalted butter
1/2 teaspoon kosher salt
1 cup all-purpose flour
5 eggs
1 cup + 2 tablespoons grated Gruyère cheese
1/3 cup mixed seeds (poppy, sunflower, and sesame)
Flaky sea salt, such as Maldon, for finishing
Preheat the oven to 425 degrees F.
Place the milk, butter, and salt in a Dutch oven or heavy-bottomed saucepan and set it over medium heat. Bring it to a boil, then reduce to a simmer and add the flour, stirring constantly with a wooden spoon. Continue to cook, stirring as you go, until the mixture comes together in a ball and leaves a film on the spoon.
Immediately transfer the dough to the bowl of a stand mixer fitted with the paddle attachment and mix on low speed for a few minutes to let it cool slightly. Add 4 of the eggs, one at a time, mixing well between each. It’ll look a bit wet at first but keep beating and it will smooth out. Add 1 cup of the cheese and beat until combined.
Spoon the dough into a pastry bag with a wide tip (or use a Ziplock bag and snip the corner) and pipe large dollops (about 2 tablespoons each) of the dough onto a parchment-lined baking sheet (I used a Silpat).
Beat the remaining egg and brush it onto the tops. Sprinkle the remaining 2 tablespoons of cheese, the flaky salt, and the seeds evenly over the dough.
Bake for about 20-24 minutes, until puffy and light golden brown. Remove from the oven and serve hot.