Bring 4 cups water to boil in heavy large saucepan over medium-high heat. Add salt. Gradually whisk in semolina. Boil until thick, whisking often, about 3 minutes. Remove from heat.
Heat butter in heavy medium skillet over medium-high heat. Add garlic, ginger, curry leaves, chile, mustard seeds, and cumin seeds; sauté until aromatic, about 1 minute. Add tomatoes, peas, and cashews. Sauté mixture until cashews begin to color, about 2 minutes. Stir mixture into semolina. Season with salt and pepper. Rewarm, if necessary.
*Semolina flour is available at some supermarkets and at specialty foods stores and Italian markets. Farina can be ordered from amazon.com.
**Also known as kari patta; available at Indian markets.
***Sold at specialty foods stores, Indian and Asian markets, and adrianascaravan.com. If unavailable, substitute brown mustard seeds.
