Step #1 Heat olive oil in medium sized pan, over medium high heat.
Step #2 Cut 1 to 1/1-2 inches off the bottom of the asparagus spears, discard those pieces.
Step #3 Then cut the spears into 1 inch pieces with a diagonal cut.
Step #4 Toss asparagus & onion into the olive oil in the pan & stir this to coat well.
Step #5 Use salt & pepper to your liking.
Step #6 Continue stirring, & when the asparagus & onion mixture sizzles, drop in the butter & stir it around so it melts, mixs in & coats the aspargus mixture.
Step #7 Now turn the heat down to medium or medium low (depending on your stove), cover the pan & let it simmer for a few mins.
Step #8 Stir it a couple times & only cook this until the asparagus turns a light green & softens a bit.
Step #9 Now stir in the the mushrooms, raise the heat back to medium high & cook (stirring) just until the mushrooms begin to shrink & soften.
Enjoy the Betsy's Asparagus & Mushroom Saute recipe