Boxty with Cheddar and Herbs

Ingredients:

• 3 tbsp unsalted butter, plus more as needed
• 1 large onion, finely chopped
• 1 kg potatoes, peeled and chopped
• 1/4 cup milk
• 1 large egg yolk
• 1/3 cup flour + extra for work
• 0.5 cup grated Irish cheddar (about 60 g)
• 3 tbsp finely chopped fresh parsley
• Finely chopped fresh chives, for sprinkling

Preparation:

1. In a medium skillet over medium heat, melt 2 tablespoons of butter. Add the onion, season with salt, and cook, stirring occasionally, until very soft and golden brown, 25-30 minutes. Let cool.
2. Meanwhile, place the potatoes in a saucepan, cover with water to a depth of 2.5 cm, and season with salt. Bring to a boil, then reduce heat and simmer until tender, 10-12 minutes. Drain and transfer the potatoes to a large bowl, add milk, and mash until smooth. Let cool for at least 30 minutes.
3. Preheat the oven to 120°C (250°F) and line a baking sheet with parchment paper. Add the fried onion, egg yolk, flour, cheese, parsley, 1 teaspoon of salt, and a pinch of freshly ground black pepper to the potatoes; stir until smooth. Scoop 1/4 cup of the potato mixture into each pan and form twelve 7cm (3-inch) patties on a lightly floured work surface.
4. In a large nonstick skillet, melt the remaining 1 tablespoon butter over medium-high heat. Fry the potato pancakes, a few at a time, until golden brown on the bottom, about 4 minutes. Carefully flip, adding more butter to the pan if necessary, and continue frying until golden brown on the other side, another 3-4 minutes. Transfer the boxty to the prepared baking sheet and keep in a warm oven until ready to serve. Serve sprinkled with green onions.