Heat ½ tablespoon olive oil in a pan over medium heat. Add the sliced red onions and cook, stirring occasionally, for about 5-7 minutes until soft and caramelized.
Add the asparagus to the pan, drizzle with the remaining olive oil, and season with salt and black pepper. Sauté for 3-4 minutes, stirring occasionally, until the asparagus is tender and slightly charred.
Drizzle fresh lemon juice over the asparagus and onions. Stir gently to combine.
Plate the dish and serve immediately as a side or with a protein of choice.
Notes
Cooking Tip: For extra flavor, add a pinch of red pepper flakes or a sprinkle of grated Parmesan before serving.
Customization: Swap red onions for shallots or add minced garlic in the last minute of cooking for a deeper flavor.
Make-Ahead: Caramelize the onions in advance and store them in the fridge for up to 3 days to speed up prep time.