Start by trimming the woody ends off the asparagus, snapping or cutting about 1-2 inches from the bottom of each stalk. Rinse the asparagus under cold water and pat dry.
Heat your large skillet over medium heat. Add the butter and olive oil, letting the butter melt gently until it begins to foam and turn a light golden color, releasing a nutty aroma.
Lay the asparagus in a single layer in the skillet, pressing down slightly so they make contact with the hot surface. Cook undisturbed for about 2 minutes, until the bottoms develop a slight sizzle and a light golden hue.
Use tongs or a slotted spoon to turn the asparagus, ensuring even contact with the pan. Add the sliced garlic, spreading it over the stalks as you toss, and cook for another 2-3 minutes. The garlic should become fragrant and slightly golden, filling the kitchen with a warm aroma.
Continue sautéing, tossing frequently, until the asparagus turns bright green and begins to soften but remains slightly crisp, about 2 more minutes. The tips may develop a slight char and smoky scent.
Remove the skillet from heat. Squeeze fresh lemon juice over the asparagus for brightness, and season with salt, black pepper, and red pepper flakes if using. Toss gently to combine.
Transfer the sautéed asparagus to a serving plate. Serve immediately while hot, garnished with an extra squeeze of lemon if desired, and enjoy the fragrant, tender bites.
