1/4 small red onion, thinly sliced
2 tbsp fresh lemon juice
16 spears fresh asparagus (about 1 bunch), trimmed
3 tbsp olive oil, divided
Sea salt and ground black pepper, to taste
2 cups baby arugula
2 cups cherry tomatoes, halved
1/2 cup crumbled feta cheese
1/4 cup toasted unsalted hazelnuts
In a small bowl, soak onion in lemon juice for 10 to 15 minutes. Drain, reserving lemon juice.
Meanwhile, preheat a grill or grill pan to medium-high. In a large bowl, toss asparagus with 1 tbsp oil and season with salt and pepper. Add to grill and cook for 2 to 3 minutes per side. Remove from heat and cool to room temperature.
Prepare topping (if using): In a small food processor, pulse cheese and hazelnuts into rough crumbs.
Prepare dressing: In a small bowl, whisk remaining 2 tbsp oil and reserved lemon juice. Season with salt and pepper.
Divide arugula among plates and top with tomatoes, asparagus, onions and dressing, dividing evenly. Garnish with topping.