Variable in Graph Request Body (PowerShell)

Working off the following URL: https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fgraph%2Fapi%2Fpasswordauthenticationmethod-resetpassword%3Fview%3Dgraph-rest-beta%26tabs%3Dhttp&data=04%7C01%7CJonesL%40duvalschools.org%7C997660b94b6e446de25508d9370bfc97%7C8deb1d4dd0a44d0489aef7076cbaa9fb%7C1%7C0%7C637601346885178418%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ZVLJ3SH%2FHpLXNgV1uJAZqdCpLfvKqy%2Bb3kn7epZeUDA%3D&reserved=0

When I execute the following command in my PowerShell script it works flawlessly

$PWCBody = '{
"newPassword" : "ssd$$FGW!!",
"forceChangePasswordNextSignIn" : true
}'

$PWCURI = "https://graph.microsoft.com/beta/users/XXXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/authentication/passwordMethods/XXXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX/resetPassword"
$PWChange = Invoke-RestMethod -Uri $PWCURI -Headers $HeaderDelegate -body $PWCbody -Method POST -ContentType "application/json"

However, when I change the Request Body newPassword to variable I get a (403) Bad Request. 

$PWCBody = '{

"newPassword" : $password,
"forceChangePasswordNextSignIn" : true
}'

How can i handle a variable in a Requested Body that's surrounded by single quotes?

Thank You,

-Larry