Cut potatoes into 1-1/2-inch pieces. Place in microwave-safe dish; cover with vented plastic wrap. Microwave on HIGH 6 to 8 minutes or until just tender, stirring once. Cool slightly.
Cut beef Top Sirloin Steak into 1-1/4 inch pieces. Combine beef, mushrooms, tomatoes, potatoes, olive oil, and steak seasoning in a large bowl; toss. Alternately thread beef and vegetables onto metal skewers.
Place kabobs on grid over medium, ash-covered coals. Grill, 9 to 12 minutes (over medium heat on preheated gas grill, 8 to 10 minutes) for medium rare (145°F) to medium (160°F) doneness, turning once and brushing with sauce during last 5 minutes. Remove from grill and brush with remaining sauce. Garnish with remaining rosemary, parsley mixture.
In a small sauce pot combine butter, parsley, garlic, and rosemary. Melt butter mixture over low heat either on the stove top or on your grill; until melted. stir occasionally.
Nutrition information per serving, 1 kabob: 310 Calories; 171.9 Calories from fat; 19.1g Total Fat (9.3 g Saturated Fat; 0.5 g Trans Fat; 1 g Polyunsaturated Fat; 7.1 g Monounsaturated Fat;) 86 mg Cholesterol; 510 mg Sodium; 12 g Total Carbohydrate; 1.8 g Dietary Fiber; 2.2 g Total Sugars; 23 g Protein; 0 g Added Sugars; 33.8 mg Calcium; 2 mg Iron; 726.8 mg Potassium; 0.2 mcg Vitamin D; 0.2 mg Riboflavin; 10.8 mg NE Niacin; 0.6 mg Vitamin B6; 1.2 mcg Vitamin B12; 244 mg Phosphorus; 4.3 mg Zinc; 30.3 mcg Selenium; 99.8 mg Choline.
This recipe is an excellent source of Protein, Niacin, Vitamin B6, Vitamin B12, Zinc, and Selenium; and a good source of Iron, Potassium, Riboflavin, Phosphorus, and Choline.