This fit and fresh dish features top sirloin, my favorite cut of lean beef, paired with farmer’s market-fresh produce, flavors of the Far East, and some funky South Congress food truck fusion. Keep Austin weird!
Toss together beef with garlic, water, soy sauce and sesame oil. Let marinate in the refrigerator for at least 30 minutes or up to 2 hours.
Meanwhile, stir together hot water with cornstarch until dissolved. Stir in watermelon juice, lime juice, 2 tablespoons soy sauce and 1 to 2 tablespoons Sambal Oelek according to personal preference for spicy heat.
Drain and discard marinade from beef. Heat 1 tablespoon oil in large skillet over high heat. Add one-half of beef to skillet and brown for 45 seconds without stirring. With tongs, quickly turn beef and cook additional 30 seconds or until barely browned. Take care not to overcook. Transfer to a warm plate immediately. Repeat browning with remaining 1 tablespoon oil and beef.
Add final 1 tablespoon oil in same skillet and bring to medium-high heat. Add green beans and peppers and stir-fry for 2 minutes or until crisp-tender. Add matchstick carrots and ginger and stir-fry an additional 1 minute. Add cooked beef and watermelon juice-chili sauce mixture and stir-fry another 1 minute, or until slightly thickened. Remove from skillet from heat and stir in watermelon.
Garnish with chopped green onions and sprouted watermelon seeds. Serve immediately with prepared udon noodles.