PREPARATION:
- Cut beef lengthwise in half, then crosswise into 1/8-inch slices; cut each slice into 2-inch pieces. Toss beef with garlic in medium bowl. Press tofu lightly between paper towels; cut into 3/4-inch triangles or squares.
- Blend broth, soy sauce and sherry into cornstarch in small bowl until smooth.
- Heat large, deep skillet over medium-high heat. Add 2 teaspoons peanut oil; heat until hot. Add half of beef mixture; stir-fry 2 minutes or until beef is barely pink in center. Remove to large bowl. Repeat with remaining beef. Remove and set aside.
- Add remaining 2 teaspoons peanut oil to skillet. Add leek and bell pepper; stir-fry 3 minutes or until bell pepper is crisp-tender. Stir broth mixture; add to skillet with tofu. Stir-fry 2 minutes or until sauce boils and thickens and tofu is hot, stirring frequently.
- Return beef along with any accumulated juices to skillet; heat through. Stir in sesame oil, if desired. Serve over spaghetti, if desired.
