Trim the woody ends off the asparagus and rinse thoroughly under cold water. Pat dry with a towel.
Heat a large skillet over medium-high heat, then add the butter and olive oil. Let the butter melt completely until it starts to foam and smell nutty.
Arrange the asparagus spears in a single layer in the hot skillet, pressing them down gently. Sauté for about 3-4 minutes, turning occasionally with tongs, until they begin to blister and turn a vibrant green.
Add the minced garlic to the skillet, spreading it evenly among the spears. Cook for about 30 seconds, until fragrant and golden, making sure not to burn the garlic.
Sprinkle a pinch of chili flakes if using, and then squeeze fresh lemon juice over the asparagus. Toss everything gently with tongs to coat evenly with the garlic butter and distribute the flavors.
Cook for another 1-2 minutes until the asparagus is tender yet crisp, with a glossy, slightly caramelized surface and a fragrant garlic aroma.
Remove the skillet from heat and transfer the asparagus to a serving plate. Drizzle any remaining garlic butter from the pan over the top, and season with salt and freshly cracked black pepper to taste.
Serve immediately while hot, enjoying the tender-crisp texture and the rich, aromatic coating of garlic butter.
