Baked Belgian Cottage Pie with Leeks, Endive and Mustard-Mash (Stoemp Style)

A crisp-topped cottage pie meets Belgian stoemp: buttery mustard-scented mashed potatoes blanket a savory beef, leek and endive filling, finished in the oven until bubbling and deeply golden. It’s weeknight-friendly, uses April produce you’ll find anywhere, and leans on the oven for even heat and hands-off time.