Make crust: In a large saucepan over medium heat, melt marshmallows and butter, stirring to combine. Remove from heat and stir in Fruity Pebbles.
Grease a springform pan with cooking spray, then press mixture into pan and up the sides. Let cool.
Meanwhile, make filling: In a large bowl using a hand mixer, beat together cream cheese and sugar until light and fluffy, then add vanilla and salt. Stir in Cool Whip until no lumps remain, then fold in Fruity Pebbles.
Spoon filling into cooled crust and refrigerate until set, at least 4 hours and up to overnight.
Remove cheesecake from pan and garnish with more Fruity Pebbles before slicing and serving.
Recipe by 5* trending recipes with videos at https://food.theffeed.com/2019/02/07/fruity-pebbles-cheesecake/