1. Heat the oil and butter in a 12-inch skillet over medium-high heat. When the butter has melted, add half of the asparagus to the skillet with the tips pointed in one direction; add the remaining asparagus with the tips pointed in the opposite direction. Using tongs, distribute the spears evenly (the spears will not quite fit into a single layer); cover and cook until the asparagus is bright green and still crisp, about 5 minutes.

2. Remove the cover and increase the heat to high; season the asparagus with salt and pepper. Cook until the spears are tender and well browned along one side, about 7 minutes, using tongs to occasionally move the spears from the center of the skillet to the edge to ensure all are browned on 1 side. Transfer asparagus to a serving dish, season with salt and pepper to taste, and if desired, squeeze the lemon half over the spears. Serve immediately.

For garlic and parmesan:

Heat 2 tablespoons olive oil and 3 medium garlic cloves, sliced thin, in a 12-inch skillet over medium heat; cook, stirring occasionally, until the garlic is crisp and golden but not brown, about 5 minutes. Using a slotted spoon, transfer the garlic to a paper towel-lined plate. Follow the recipe for Pan-Roasted Asparagus, adding butter to the oil in the skillet. After transferring the asparagus to a serving dish, sprinkle it with 2 tablespoons grated Parmesan, the toasted garlic, and lemon juice. Season with salt and pepper to taste; serve immediately.