"Extra yumminess" means something that tastes even better than it normally would.
Full definition
I thought the cheese added that
extra yumminess.
Our rugged snow pants are loaded with smart features (and stylish details) that will see him through hours of outdoor fun: water - repellent fabric with warm Thermolite ® fill for bulk - free warmth, with
the extra yumminess of fleece - lined zip hand pockets; easy - on elastic - back waist and zip fly; adjustable suspender straps; elasticized snow cuffs to keep legs dry; even reinforced seat, knees, and hems for extra durability where he needs it most.
That is all
the extra yumminess added when you double up on the butter and spices.