The Bavarian Cream (or custard if you want that) is much less time consuming and easier to prepare, so there's no problem in putting that together from scratch. The last thing you need are strawberries, raspberries, or blueberries. Any of these fruits will do just fine; however, strawberries should be your first choice! Using a selection of strawberries, prepare them by slicing them to about 1/8 inch thickness.
Begin by defrosting two puff pastry sheets for a couple of hours. Place them in the fridge until ready to use, as you certainly want the dough to be well chilled which will result in a much puffy rise. Preheat your oven to 425 F. Roll out the puff pastry on a floured cutting board and roll out the sheet until it is about 12" x 12". Using a 2 to 3 inch cookie cutter, begin to cut little round disks, discarding the excess left over. Use a mini cupcake pan and place a disk in each slot as you would if you were making little tart shells, but don't press down too hard (and no poking holes in the pastry with a fork on this one). Using a pastry brush, apply a very thin layer of egg wash to each one. Bake for about 12 to 14 minutes or so, keeping a close eye on them so they don't burn. They should puff up to really nice round puff pastry balls. Remove from the oven and allow to cool. Once cooled, you can take a very sharp knife and slice them horizontally right at the seam.
The Bavarian Cream is not difficult to prepare. In fact, you could prepare it before you start anything else which would give it time to cool down in the fridge. Get the following ingredients together:
2 tablespoon of powdered gelatin
1/2 cup of cold water
1/2 cup of sugar
2 cups of heavy whipping cream
1/2 cup of cold water
1 3/4 cups of milk
1 pinch of salt
4 egg yolks
1 teaspoon of vanilla extract
Start by diluting the powdered gelatin in the water, stirring well. Set aside.
Using a medium size bowl, whisk briskly the egg yolk, sugar, and salt. If you want, you may use an electric hand mixer with a whisk attachment. Whisk until the egg yolk doubles in size and becomes a light yellow and silky.
In a sauce pan, bring the milk to a boil; however, before it comes to a boil, take a few tablespoons of the milk and slowly add it to the egg yolk, stirring the egg yolk constantly so that it doesn't clump. You are wanting to bring the temperature of the egg yolk up to where it won't cook it when you slowly pour the rest of the milk into the bowl. Once the milk has come to a boil, add it slowly to the yolk and stir well with a hand whisk. Return the combination to the sauce pan and heat while stirring, over medium. At this point, you can use a wooden spoon to stir. Once the spoon can be nicely coated with the mixture, it's ready. Remove from heat, pour it through a strainer into a bowl, mix the gelatin into the custard so that it melts completely, and cover the surface of the custard with a sheet of plastic wrap. Set aside and allow to cool.
Once the custard has cooled, whip the heavy cream, along with the vanilla extract until you have medium stiff peaks. Carefully fold the cream into the custard in 3 equal parts. Don't over stir so that you don't lose the air that whipping the cream created. Once fully folded, place the bowl in the fridge for about an hour.
Once cooled, you're ready to assemble your little puff pastries. Using a small teaspoon, place some of the custard to the bottom half of each puff pastry shell, followed by a couple of slices of strawberries. Finish with just a little dab of custard and place the top half of the pastry puff on top of the custard. Feel free to add a couple of drops of white chocolate syrup on the top and place a raspberry over the syrup for a final touch. You will be delighted at the outcome and so will your friends and family. These little morsels are sinfully good! Enjoy.