Preheat oven to 350°. Place 6 greased custard cups in a deep roasting pan.
Add 1 tablespoon butter, cauliflower and leeks in a covered saucepan. Season with salt and set over low heat. Cook, covered for about 30 minutes, stirring occasionally, until veggies are soft and fragrant. Remove from heat and purée with ¼ cup milk until smooth. Transfer to a mixing bowl.
In a small saucepot, bring the remaining milk to a simmer. In another small or medium saucepot, place 2 tablespoons butter and nutmeg, set over medium heat. When the butter melts and the nutmeg sizzles, add flour and whisk to combine. Cook and stir the roux for a couple minutes to bloom the nutmeg, then slowly whisk in the hot milk. Continue to cook over medium heat, whisking constantly until sauce thickens so the whisk leaves a trail. Season with a generous pinch of salt and let cool a few minutes before proceeding.
Add eggs and Parmigiano to the cauliflower mixture, stirring to combine. Stir in the warm béchamel. Taste for seasoning. Divide the sformato mixture among the custard cups.
Fill your teakettle and bring to a boil. Add boiling water to roasting pan until it reaches halfway up the sides of the custard cups. Bake about 30 minutes until the custards are just set. Remove from water and cool at least 30 minutes before serving. (May be made a day in advance, refrigerated overnight and warmed through for serving.)
Serve the sformato either in the custard cup or un-molded. To un-mold, run a thin knife around the edge of the cup, invert on top of a serving plate and gently tap until released. Served drizzled with extra-virgin olive oil. Makes 6.
<em>Recipe by Chef/owner Joe Simone, Simone’s, Warren</em>