Wash the asparagus spears and snap off the bottoms of the asparagus. Keep them whole or slice them into 2-inch pieces.
Cook:
Heat up a large skillet over medium-high heat. Once hot, melt the butter. Add the garlic and sauté for 30 seconds until fragrant.
Add the asparagus spears to the pan, red pepper flakes or dried peppers, Sriracha (if using), salt, and pepper. Stir to distribute onto all the asparagus spears.
Continue cooking, stirring to ensure the spears don't burn, for about 3 minutes, until the asparagus is cooked but still crispy and bright green.
Let them sit & serve:
Turn off the heat and let them sit on the pan for about 2 minutes before serving. They'll continue to cook and get a bit more tender but without being directly over a heat source.