Heat 2 tablespoons oil in a heavy-bottomed saucepan over medium heat. Add cumin seeds and stir constantly for 1-2 minutes until fragrant, taking care not to burn them.
1 tsp cumin seeds
Add diced onion to the pan and cook for 5-7 minutes, stirring occasionally, until translucent and lightly golden at the edges. Then stir in minced garlic and ginger and cook for another 1-2 minutes until fragrant.
1 medium onion, 3 cloves garlic, 1 tbsp ginger
Sprinkle curry powder over the onions and stir for 30 seconds to bloom the spices. Add chopped tomatoes and 1 cup water, then bring to a simmer and cook for 5 minutes until the tomatoes break down and sauce thickens slightly.
2 medium tomatoes, 2 tbsp curry powder
Add cubed potatoes and sliced carrots to the sauce and stir to coat. Cover the pot and simmer for 10 minutes. Then add cauliflower florets and green beans and continue simmering uncovered for 10-12 minutes until all vegetables are tender when pierced with a fork.
2 medium potatoes, 2 medium carrots, 1 cup green beans, 1 cup cauliflower
Taste the sauce and adjust salt as needed. Stir in coconut milk if using, then turn off heat and let the curry sit for 5 minutes so the flavors settle and the sauce clings to the vegetables.
salt, ½ cup coconut milk
