Peel the potatoes and cut them into smaller wedges to speed up boiling. Bring a pot of water to a boil, season with salt, and add the potatoes. Peel the garlic and lightly crush the cloves, then add them to the pot with the potatoes.

Boil the potatoes and garlic until the potatoes are soft. Then add the spinach to the boiling water and cook for about 1 minute, until the spinach wilts.

Drain the water. Mash the potatoes, spinach, and garlic together with 4 knobs of butter, salt, and pepper until smooth. (If you don’t have a potato masher, you can use a fork.)

In a bowl, mix wheat flour with a pinch of salt and pepper. Coat the fish fillets on both sides with the flour mixture.

Fry the coated fish on medium heat for about 5 minutes per side, until golden brown. Remove the fish from the pan and add 6 knobs of butter to the same pan. Heat the butter over medium heat for 1–2 minutes, until it turns golden and gives off a nutty, caramel-like aroma. Remove from heat, then add capers and the juice of half a lemon. Season with salt, pepper, and a pinch of sugar.

Serve the spinach mashed potatoes with the pan-fried fish and the brown butter caper sauce. Add a lemon wedge on the side.