Heat large skillet over medium high heat. Add 1 Tbsp. of the oil to the pan. Swirl to coat.
Add half the beef to the pan and cook for about 8 minutes or until well browned. Make sure to turn meat to brown all sides.
Place cooked beef in a crockpot and sprinkle with 1/8 tsp. Kosher salt.
Repeat above steps for remaining beef.
Add onions to pan and cook 1 minute until browned and add to crockpot.
Add garlic to pan and sautè 1 minute, then add tomato paste and cook for an additional minute, stirring constantly.
Add half cup of wine, scraping brown bits from the bottom of the pan. Cook wine for about 2 minutes until liquid reduces by half.
Add beef stock and pepper and bring to simmer. Pour stock mixture into slow cooker.
Top beef with mushrooms and carrots.
Cover and cook on Low for 7 1/2 hours
Strain mixture from crockpot through colander over a large Dutch over or pot. Bring liquid to a boil and cook 6 minutes until liquid is reduced to about 2 cups. Stir in remaining salt.
Combine remaining 2 Tbsp. of wine and flour. Stir with a whisk to form a slurry. Stir slurry into cooking liquid, cook one minute until thickened and bubbly, stirring constantly. Pour over beer and toss to combine.