1/4 cup vegetable oil
1 lb yukon gold potatoes, diced into large pieces
1 tsp yellow mustard seeds
4 tsp ginger, peeled and finely chopped
3 garlic cloves, chopped
1 tsp ground cumin
3/4 tsp salt
1/2 tsp ground coriander
1/4 tsp cayenne pepper
1 cauliflower, about 2 lb, trimmed and cut into 1 inch chunks
1/2 cup water
1 tbsp unsalted butter
Heat 3 tbsp oil in a large cast iron frying pan on medium high heat, add the potatoes and season with salt. Cook, tossing and scraping any browned bits from the bottom of the pan, until potatoes are beginning to brown. Set potatoes aside when done.
Reduce heat to medium, add the rest of the oil to the pan and heat. Add in the mustard seeds and toast until starting to pop. Add the ginger, garlic, cumin, salt, coriander, tumeric and cayenne and cook until fragrant.
Add in the cauliflower and stir to coat with spices. Return the poatoes and add the water. Stir to combine well and cover with a lid. Cook cauliflower until tender, about 10 minutes. Add in butter and melt over vegetables. Taste and adjust seasoning, then serve.