1. Preheat your oven to 350°F (180ºC). Butter 9×13-inch (3 L) baking dish.
2. In a large pot of boiling salted water, cook cauliflower for 5 min. Drain; set aside in a bowl.
3. Meanwhile, cook bacon in a large skillet set over medium heat for 5 min or until crispy. Set aside on paper towels. Discard all but 2 tsp (10 mL) fat. Add leeks to skillet; cook, occasionally stirring, for 5 to 7 min or until very soft and starting to turn golden. Transfer to bowl with cauliflower; add bacon.
4. Over medium heat, bring to simmer 1 cup (250 mL) of milk and butter. Whisk flour into remaining 1 cup (250 mL) milk; gradually whisk into saucepot. Whisk constantly until the sauce thickens. Whisk in Swiss, Parmesan and salt until cheese is melted. Remove from heat and set aside.
5. Pour over cauliflower mixture, stirring until well coated. Transfer to buttered dish.
1. In a bowl, stir together breadcrumbs, cheese and butter. Sprinkle over the dish. Bake for about 30 min or until golden on top and heated throughout.
Recipe adapted from Dairy Farmers of Canada, dairygoodness.ca