Jamie Vardy ended his recent goalscoring drought as he opened the scoring with a swift move after 23 minutes.
Just as couple of minutes later, a rare Jonny Evans goal doubled the Foxes lead.
Before Kelechi Iheanacho continued his world class form and added a third before the break.
Superb Vardy performance
After the 34-year-old has been frustrated infront of goal since the turn of the year, last night was a huge confidence booster for him.
The former England international scored the opener, in what was one of the finest plays of the season, with Timothy Castagne assisting him.
Vardy also assisted Iheanacho's goal to make it 3-0. He did some great work down the left wing similarly to the winning goal in the Fa Cup semi-final last weekend.
In what was a Harvey Barnes-esque driving run, Vardy cut it back for Iheanacho to finish smartly.
Vardy and Iheanacho are rapidly becoming one of the deadliest strike partnerships in the league.
Brick wall defence
It was yet again another inch perfect performance from Leicester's back line. Operating in a back three/five once again worked a treat.
Having Evans in the middle of two dynamic centre halves in Wesley Fofana and Çağlar Söyüncü allows for freedom, whilst also maintaining a solid line.
In the four games that the three have played together, they have kept three clean sheets and have only conceded one goal.
Also a very special mention to the wingbacks Luke Thomas and Castagne, they covered every blade of grass on their respective sides, with the latter managing to grab an assist as well.
Thomas slotted in perfectly at left wing-back, and at only 19 he is showing terrific maturity in the timing of his tackles etc. And for somebody that stands at only 5'10, he leaps like a salmon to head the ball clear at times.
Albion's time up?
In a game where they absolutely needed to get points from, it was a bitterly disappointing performance from the Baggies.
Sam Allardyce didn't get it right tactically, and there was error after error from the West Brom defence, where it easily could have been six or seven.
They're nine points off of 17th place Burnley. with six games to go, it isn't impossible for them to stay up, but Fulham in 18th are also three points clear of them. However, Albion do have a game in hand on them.
The black-country side don't have an easy run-in either.