2large onions,sliced and separated into rings (16oz)
1/4cupfresh, high-quality sweet paprika
1/2(6 oz can)tomato paste
Season the beef with a teaspoon of kosher salt and 1/4 teaspoon black pepper.
In a large, 12-inch skillet, heat 1 tablespoon olive oil over medium-high heat, about 3 minutes. Add half the beef in a single layer and brown on all sides, about 5 minutes total. Remove to a platter with a slotted spoon, add the remaining olive oil, and brown the remaining beef. Remove to a platter.
Lower heat to medium. Add the onions and cook, stirring, just until tender but not browned, about 5 minutes. Add the garlic, the paprika and the cayenne and cook, stirring, 30 seconds. Remove from heat.
Place the browned beef and the onion mixture in the slow cooker, using a spatula to scrape everything off the skillet and mixing it all together in the slow cooker.
In a medium bowl, whisk together the beef broth, tomato paste, and the remaining salt and pepper. Pour over the beef and onions and stir to combine. Cover, and cook on low for 8 hours.
When done, whisk the cornstarch with the water until smooth. Stir into the beef mixture. Set to high, cover, and cook 30 more minutes, until the sauce thickens.