In a large ziploc bag place beef tips, flour and seasonings listed in ingredient listing above for "Coating".
Close bag and shake well until all beef tips are coated.
In a large skillet or dutch oven, heat 2 TBS cooking oil and 1 TBS butter to a sizzle. Place beef tips in a single layer. (I cooked the beef tips in two batches.)
Sear and brown on each side for 2-3 minutes. Place seared meat in bottom of crockpot. Complete next batch, if needed.
Add celery, carrots, and onions to skillet with 1 TBS butter or cooking oil if needed. Season with salt & pepper. Stir until vegetables are lightly browned. Stir in tomato paste and 1/4 tsp each of garlic powder, onion powder and paprika. Slowly pour in beef broth, turn off burner and pour mixture over beef tips in the crockpot. Stir well.
Place lid on crockpot and cook for 5-6 hours on low or 3-4 hours on high. (These are small pieces of beef so they won't take as long to cook as a full roast.) But make sure to cook long enough so the beef tips are very tender.
Serve over mashed potatoes, rice, or pasta. Garnish with fresh parsley, if desired.