Measure and prepare all ingredients before starting. Combine the flour, salt, and sugar in a container and set aside. Crack the eggs into a separate bowl and set aside.

Add the butter and milk to a high-sided, heavy-bottomed saucepot. Heat on high until the milk just reaches a boil and the butter is fully melted simultaneously. Do not allow the milk to continue boiling.

Add the flour mixture all at once and stir with a wooden spoon to incorporate. Once the mixture begins to thicken, stir vigorously to smooth out any lumps.

Continue cooking on high heat, stirring constantly, until a cohesive dough (panade) forms, pulls away from the sides of the pot, and leaves a coating on the bottom. This takes approximately 2 minutes and indicates enough moisture has evaporated for a pipeable paste.

Transfer the dough to the bowl of a stand mixer fitted with the paddle attachment. Beat on medium-high to release steam.

Once the dough stops steaming, add the eggs one at a time on medium speed, beating fully after each addition. Continue until the paste is smooth, shiny, and passes a consistency test: drag a finger through the paste and the trench should close slowly, and the paste should fall from the spatula in a thick V shape. If all 5 eggs are incorporated and the paste is still too stiff, beat an additional egg separately and add it in stages, testing after each addition.

Add any mix-ins called for in your specific recipe. Transfer the paste to piping bags. Use immediately or refrigerate.