Heat the oven to 175C/346F.
Add the potato cubes into medium pot, cover with water and bring to boil over medium heat.
Reduce the heat to low and simmer for 5 mins, then drain.
Line a baking sheet with parchment paper and add the potatoes, cauliflower florets, 1 tsp curry powder, chili flakes, drizzle with olive oil and toss to coat evenly.
Roast for 30 minutes, then add the peas and green beans, toss to combine and roast for 7 more minutes.
Meanwhile, prepare the sauce.
Add 1 tsp oil into a cast-iron skillet, add the onion and cook for 2 minutes over medium heat, stirring frequently, until translucent.
Add the garlic, ginger and the rest of spices, and cook for 2 minutes over low heat.
Add the diced tomatoes with their juices, coconut milk, coconut sugar, and mix to combine.
Bring to boil over medium heat, then simmer for seven minutes over low heat.
Add the lemon juice, mix and remove from the heat.
Divide the sauce into serving bowls, top with roasted veggies, garnish with fresh parsley and mint, and serve warm with coconut yogurt.