Hi! I'm looking for a recipe for a non-perishable buttercream that tastes like Bavarian cream (custard-like), but has a firm consistency similar to chilled whipped butter. I need a buttercream that can withstand 12+ hours in room temperature and is stable enough for a 3 tier cake (9", 7", 5") covered in fondant.

I'm making a small wedding cake as a surprise for my friends who are having a "secret" getaway wedding in Vegas. I'm bringing the cake layers as my carry-on, but will make the filling at the hotel. My hotel room has a 2-burner stove range and only a mini refrigerator, so I likely will not be able to store the cake in the fridge. Since this is a surprise, I'll have to finish the cake in the morning, join the group for activities, and come back to the hotel in the evening to get the cake for dinner.

I've read many posts on CC for "shelf-stable cream" and "firm custard buttercream," but have not found a combination of the two. I'm thinking of a few options and would love your feedback!
1.) RLB's SILK Meringue Buttercream
2.) Mixing sleeve Bavarian cream with IMBC/RLB's Mousseline
3.) IMBC/Mousseline with a few drops of Lorann Bavarian cream oil flavoring (Has anyone used this product?)

I'm so sorry for the lengthy post, but I'd greatly appreciate any feedback/suggestions!
-Christina

FYI a mini fridge is big enough for your cake.

I would say, keep the roulette in the casino and make food safety your priority #1.

Better first of all check the NV cottage bakery state laws.

As a practical rule of thumb to stay on the safe side: ALL products with butter will taste much better under refrigeration. ALL products with milk or cream or cream cheese or eggs will require to be chilled.

The utterly artificial sleeve stuff could be mixed with instant pudding powder (a brand that does NOT contain dry milk). By adding buttercream to any other material, the whole mixture acquires the safety rules of butter.

It sounds like this cake is for personal consumption, so I'm not sure why cottage industry laws would be of concern.

I don't think 12 hours in an air conditioned room is going to be a problem, as long as all of your ingredients are top quality, you cook and cool the custard appropriately, and crank up your air conditioning as high as possible. If you're concerned though, why not check with the hotel to see if they will store it in their refrigerator for you? It won't hurt to ask.

For a custard based buttercream, I use this one from Capriel (Pence)'s Desserts:

2 cups half and half
1 egg yolk
3 tbl cornstarch
1 lb butter, room temp
3/4 cup sugar
1/8 tsp salt
2 tbl vanilla

Whisk half and half, egg yolk, and cornstarch in a saucepan until smooth. Cook over medium-high , sitrring constantly, until it comes to a boil and is very thick. Strain into a bowl and chill it over an ice bath to get it cooled as quickly as possible. Then cover with plastic wrap on the surfice and refrigerate until cold.

Whip butter and sugar on high until very light and fluffy (at least 10 minutes). Add salt and mix well. Slowly add the cold custard on low speed. Add vanilla and mix well. (Makes enough for one 9-inch layer cake.)

It wouldn't hurt to give it a test run before you go to vegas. Just to be sure it's what you want.

You can probably ask the front counter to keep your cakes in the hotel walk-in and they'll probably allow it.