Beer-Battered Asparagus

• For lemon dipping sauce:
• 1/2 cup mayonnaise
• 1 teaspoon fresh lemon juice
• 1/2 teaspoon finely grated fresh lemon zest
• 1/4 teaspoon black pepper
• For asparagus:
• 1 cup all-purpose flour
• 1 teaspoon salt
• 1 tablespoon finely grated fresh lemon zest
• 1/4 teaspoon black pepper
• 1 cup lager such as Harp (pour beer slowly into measuring cup; do not measure foam)

About 4 cups vegetable oil

• 1 lb medium asparagus, trimmed and cut into 3-inch pieces

Special equipment: a deep-fat thermometer

1. Make dipping sauce:Stir together mayonnaise, lemon juice, zest, and pepper in a small bowl. Chill, covered, until ready to use.
2. Make batter and fry asparagus:Put oven rack in middle position and preheat oven to 200°F.
3. Whisk together flour, salt, zest, and pepper in a bowl until combined, then add beer, whisking until smooth.
4. Heat 3 inches oil in a 3- to 4-quart heavy saucepan over moderately high heat until it registers 375°F on thermometer.
5. Submerge asparagus spears in batter to coat. Working in batches of 10, drag 1 at a time gently against rim to remove excess batter, then transfer to oil and fry, stirring gently to keep asparagus from sticking together, until golden, 2 to 3 minutes. Transfer as fried with a slotted spoon to a paper-towel-lined baking sheet and keep warm in oven. Return oil to 375°F between batches. Serve with lemon dipping sauce.
6. Cooks' note: Asparagus can be kept warm in oven up to 30 minutes.