Snap off the woody ends of the asparagus with your hands, ensuring each spear has a clean, fresh cut. Arrange them in a single layer on your cutting board.
Set a large skillet over medium heat and add the butter along with a splash of olive oil, if using. Wait until the butter melts and begins to bubble softly, releasing a nutty aroma—about 30 seconds.
Place the asparagus spears flat in the hot skillet in a single layer. Let them sit undisturbed for 2-3 minutes until they start to develop slight browning on the edges and smell toasted.
Use tongs to toss the asparagus gently, coating them evenly with the melted butter. Cook for another 3-4 minutes, until they turn vibrant green and are tender yet still retain some crunch.
Add the thinly sliced garlic to the skillet, spreading it evenly among the spears. Sauté for about 30 seconds until fragrant and lightly golden, making sure not to burn the garlic.
Remove the skillet from heat and squeeze fresh lemon juice over the asparagus. Toss gently to distribute, then season generously with salt and pepper to taste.
Transfer the asparagus to a serving plate, allowing it to rest for a minute to let flavors settle. Serve immediately, enjoying the glossy, vibrantly green spears with aromatic garlic and a hint of citrus.