Directions

1. Preheat oven to 400˚F (200˚C). Melt 2 tbsp (30 mL) butter in large skillet set over medium heat; cook onions and 1/4 tsp (1 mL) each salt and pepper for 8 to 10 minutes or until slightly softened. Reduce heat to medium-low; cook, stirring often, for 20 to 30 minutes or until onions are golden brown and caramelized. Stir in kale; cook for 5 to 8 minutes or until kale is wilted. Set aside.
2. Meanwhile, cook pasta according to package directions. Drain, reserving 1/3 cup (75 mL) cooking liquid. Grease 13- x 9-inch (3 L) baking dish.
3. Cook bacon in large high-sided skillet or saucepan set over medium-low heat for 5 to 8 minutes, turning occasionally, until fat is rendered and bacon is golden brown and crisp around edges. Transfer to paper towel–lined plate to drain.
4. Remove all but 1 tbsp (15 mL) bacon fat from pan; add 2 tbsp (30 mL) butter, thyme and garlic. Cook for 2 to 3 minutes or until garlic is softened. Sprinkle flour over top; cook, stirring, for 2 to 3 minutes or until smooth.
5. Slowly whisk in milk and nutmeg. Bring to boil, whisking constantly. Reduce heat to medium-low; cook, stirring constantly, for 8 to 10 minutes or until thickened slightly. Stir in mustard, Worcestershire sauce, and remaining salt and pepper. Remove from heat.
6. Stir in cheese until melted and smooth; toss with pasta, reserved cooking liquid, bacon and onion mixture.
7. Transfer to prepared baking dish. In clean skillet, melt remaining butter; toss with bread crumbs. Sprinkle over casserole. Bake for 20 to 25 minutes or until golden brown and bubbly. Let stand for 10 minutes. Sprinkle with chives.

Tip: Substitute any short cut pasta, such as penne, orecchiette, shells or cavatappi, for macaroni.