Steak with dumplings

Ingredients:

• 0.6 - 0.7 kg flank steak
• 1/3 cup sour cream
• 1 tbsp chopped fresh chives
• 1 package (450 g) of frozen potato and cheese dumplings
• 1 package (150 g) of baby spinach
• 1 tbsp unsalted butter
• 3 tbsp. grainy mustard
• 1 tbsp. l. olive oil
• 2 tsp Worcestershire sauce

Preparation:

1. Preheat grill to high heat.
2. In a small bowl, combine the mustard, olive oil, and Worcestershire sauce. Season the steak with salt and black pepper, then rub with half of the mustard mixture; let sit at room temperature for 10 minutes.
3. In another small bowl, combine sour cream and chives, season with salt and pepper to taste, and refrigerate until ready to serve.
4. Place the steak on the grill and grill for 5 minutes; turn over, brush with half of the remaining mustard mixture, and grill for another 5 minutes. Flip again and brush with the remaining mustard mixture; grill for another 5-8 minutes for medium-rare. Transfer to a cutting board and let the meat rest.
5. Meanwhile, bring a large pot of water to a boil. Add the vareniki and cook according to package directions. Place the spinach in a colander. Drain the cooked vareniki in the colander with the spinach until the spinach wilts. Return the vareniki and spinach to the pot and toss with butter; season with salt and pepper to taste.
6. Slice the steak against the grain and arrange on plates along with the pierogi and spinach. Top the pierogi with sour cream and chives.