1 cup Greek-style (2% or nonfat) yogurt*
1 cup 1/4-inch cubes English hothouse cucumber
3 tablespoons chopped fresh dill
2 tablespoons fresh lemon juice plus additional for drizzling
2 tablespoons chopped shallots
1 1/4 teaspoons aniseed, finely crushed, divided
Olive oil (for brushing and drizzling)
1 pound uncooked large shrimp, peeled, deveined, tails left intact
8 cups baby spinach leaves
3/4 cup crumbled feta cheese
Mix Greek-style yogurt, cucumber, dill, 2 tablespoons lemon juice, shallots, and 3/4 teaspoon crushed aniseed in small bowl; season tzatziki generously with salt and pepper. Chill.
Prepare barbecue (medium-high heat). Brush grill with oil. Thread shrimp onto 4 metal skewers. Brush shrimp all over with olive oil; sprinkle with salt, pepper, and remaining 1/2 teaspoon crushed aniseed. Grill just until shrimp are opaque in center, about 3 minutes per side. Divide spinach among 4 plates; drizzle lightly with additional lemon juice and olive oil. Top each with 1 shrimp skewer. Spoon tzatziki over shrimp; sprinkle with feta cheese and serve.