Prepare the potatoes by peeling and chopping your Yukon Gold potatoes into even-sized chunks. Place them in a large pot with cold water and bring to a boil. Cook for about 7 minutes or until fork-tender. Drain and set aside for mashing.

Mash the potatoes by returning them to the hot pot. Add butter, milk, salt, and pepper. Mash until smooth and creamy, adjusting seasoning. Keep warm on low heat.

In a medium pot, heat vegetable oil over medium heat. Add diced onion and carrot, sauté for 2-3 minutes until the onion is translucent.

Stir in thawed frozen corn and diced zucchini, cooking for an additional 2 minutes.

Pour in 350-400 ml of water and add Japanese curry roux. Stir until dissolved and let simmer for about 5 minutes until thickened.

Remove from heat and stir in finely chopped spinach, allowing it to wilt.

To serve, spoon mashed potatoes onto plates and top with warm curry.