Haystack Onions Recipe

Prepare the onions

Peel the onions and cut each into 1/8"–1/4" slices. Separate slices into individual rings, then use your fingers to gently pull rings apart into loose, thin 'hay' strands. Pat lightly with paper towel to remove excess surface moisture.

Make the batter

In a medium bowl, whisk together the all-purpose flour, cornstarch, baking powder, kosher salt, and black pepper. In a separate small bowl, whisk the egg with the cold sparkling water. Pour the wet into the dry and stir just until combined; a few small lumps are fine. The batter should be slightly thick but thin enough to coat the onions; add up to 1–2 tsp more water if it seems too thick.

Heat the oil

Heat 1 to 1 1/2 inches of neutral vegetable oil in a large heavy skillet or Dutch oven over medium-high heat until a deep-fry thermometer registers 350°F (175°C). If you don't have a thermometer, test by dropping a small bit of batter — it should sizzle and float immediately.

Coat and fry

Working in batches to avoid overcrowding, toss a generous handful of the prepared onion 'hay' into the batter to fully coat. Lift with a fork or tongs, letting excess batter drip back into the bowl, then carefully lower the battered onion cluster into the hot oil. Fry 2–3 minutes until golden brown and crisp, flipping once if needed so all sides crisp evenly. Remove with a slotted spoon or spider and drain on a paper-towel-lined baking sheet. Sprinkle lightly with the finishing salt while hot. Repeat until all onions are fried.

Alternative shallower fry (if using less oil)

If using only about 1 cup oil in a skillet, heat the oil to medium-high, add battered onion clusters and press slightly so they have contact with oil; fry 2–3 minutes per side until crisp and golden, then drain as above.

Keep warm

If making several batches, keep finished haystacks crisp by placing them on a wire rack set over a baking sheet in a 200°F (95°C) oven for up to 15–20 minutes while you finish frying the rest.

In a small bowl, whisk together mayonnaise, Dijon mustard, honey, apple cider vinegar, and optional yellow mustard until smooth. Taste and adjust: add a little extra honey if you prefer sweeter, or a pinch more vinegar if you want more tang. Thin with up to 1 tsp water if the sauce is too thick. Season with freshly ground black pepper.

Chill the sauce in the refrigerator for at least 10 minutes to let flavors meld. Bring to room temperature briefly before serving if chilled too long.

Arrange hot onion haystacks on a platter. Sprinkle with chopped parsley or chives and serve immediately with the honey mustard dipping sauce and lemon wedges on the side (if using).

Leftover haystacks can be reheated in a 375°F (190°C) oven for 5–7 minutes to re-crisp, but they are best served fresh.