Filling For Fondant Covered Cake

I would like a recipe for a mousse or custard base filling recipe, that I can prepare ahead of time and I will have no health problem or it will not melt inside a chiffon fondant covered cake.
For chocolate ,I have a very good moist recipe with whipped ganache filling. It works very well with fondant ,but I need a good recipe for vanilla filling that is not buttercream, because I like chiffon cake so it needs something lighter then buttercream.
Thank you

From the editor:

Try a whipped white chocolate ganache filling:

1. Scrape the seeds from one vannilla bean into 8 ounces of hot cream and allow to steep for 10 minutes.

2. Remove the bean pod and heat the cream to boiling then pour over 12 ounces of chopped white chocolate and allow to sit for 3-5 minutes.

3. Stir with a wooden spoon slowly until completely melted and smooth.

4. Refrigerate overnight then whip in a stand mixer (or a hand mixer) with the whisk attachment until light and fluffy.

Alternatively, mix up 8 ounces of cream cheese and 8 ounces of melted, cooled white chocolate, with 1 teaspoon of pure vanilla extract. Refrigerate until firm and fill your cake. It's fabulous!

Regards,
Michelle (editor)