Raita with Onion and Tomato

2 cups plain nonfat yogurt
1 cup 1/4- inch tomato cubes
1/2 cup 1/4-inch cucumber cubes
1/2 cup finely chopped onion
3/4 teaspoon salt
1/2 teaspoon roasted cumin powder**
1/4 teaspoon cayenne (optional)

Stir the yogurt well with a wire whisk in a small bowl. Add the tomatoes, cucumber, onion and salt, stir to combine.

Garnish with the roasted cumin powder and cayenne if using. Serve immediately, or cover and refrigerate until ready to serve.

**Roasted cumin powder: In a frying pan or an iron griddle, dry-roast 1/4 cup of cumin seeds over medium heat until reddish-brown to dark brown. Cool to room temperature. Grind the seeds in a blender or spice grinder and store in an airtight container.