Kosher salt and pepper
4 starchy potatoes, such as russet (about 2 1/2 pounds), peeled and cut into 1-inch cubes
2 pounds beef sirloin, cut into 1 1/2-inch cubes and brought to room temperature
5 tablespoons EVOO – Extra Virgin Olive Oil, divided
5 to 6 cloves garlic, chopped
4 sprigs fresh rosemary, chopped (about 3 tablespoons)
2 tablespoons butter
Coarse black pepper
1 teaspoon sweet smoked paprika
1/2 cup organic ketchup
2 tablespoons Worcestershire sauce
1 rounded tablespoon prepared horseradish
1 to 2 teaspoons Tabasco sauce, to taste
Watercress, arugula or other spicy greens, for garnish
Preheat the broiler. In a medium pot of boiling, salted water, parboil the potatoes for 5 minutes; drain.
Pat the beef dry; season with the kosher salt and pepper. Toss with 4 tablespoons EVOO and the garlic and rosemary. Thread as many pieces as will fit on each skewer.
In a large nonstick skillet over medium-high heat, melt the butter with the remaining tablespoon EVOO. Add the potatoes; season with salt, coarse black pepper and paprika. Cook, stirring occasionally, until browned, 10-15 minutes.
Broil the meat on the top rack, turning occasionally, until cooked, about 10 minutes.
In a bowl, make the spiked ketchup: Stir the ketchup with the Worcestershire, horseradish, Tabasco and a pinch of coarse pepper.
Squeeze the lemon over the beef and serve with the greens, crispy potatoes and spiked ketchup alongside.