In a casserole filled with salted boiling water, cook pastas al dente. Drain.
In the same casserole, heat oil at medium heat. Cook onions or sliced leks for 2 to 3 minutes.
Add honey and caramelize for 1 to 2 minutes. Set aside in a plate.
In a casserole, bring to a boil celery cream with milk while stirring. Add drained macaronis, half the parmesan and, if desired, thyme. Salt and pepper.
Transfer preparation into cooking plates. Divide caramelized onions of sliced leeks, breadcrumbs and remaining parmesan ovr pastas.
Oven bake for 15 to 20 minutes.
Did you know that...
Leeks contain large quantities of vitamins A, B1, B2, B3, B9 (folic acid) and C.