First, make your pavlova! Preheat the oven to 300° Fahrenheit, then line a cookie sheet with parchment paper. Using an 8-inch cake pan, draw a circle on the parchment paper in pencil, then flip the parchment over (you should still be able to see the circle).
Pulse your granulated white sugar in a food processor or blender until it is very fine. Then, in a large, clean and dry metal bowl, place your separated egg whites (ensuring there is NO egg yolk in them). Beat egg whites using an electric mixer on low speed (I use speed 3 on my hand mixer) until foamy and begin to hold a shape. Slowly add in 1 Tbsp of the fine sugar at a time, continuing to beat the egg whites while adding and in between additions (for at least 30 seconds in between additions) until all of the sugar has been added. You want to ensure that the eggs are beat slowly so that air is incorporated slowly and consistently, and you want to ensure that the sugar dissolves completely or your pavlova will "weep." Continue to beat egg whites after sugar has been added for 5-10 minutes (still on low speed) or until the egg whites are glossy and hold a semi-stiff peak. Finally, add in the cornstarch, cream of tartar, and salt and beat for one more minute to fully incorporate.
Take about 1/4 tsp of the meringue and place it under each corner of your parchment paper to stick it to the baking sheet so that it won't move when you shape your pavlova. Then, using a rubber spatula, carefully scoop out your meringue and fill in the drawn circle, using the spatula to pull up swoops around the outside of the pavlova to create the tall edges. Place into the oven and immediately turn the temperature down to 230° Fahrenheit and bake for 90 minutes (do NOT open the oven door during or after baking). Once baked, turn off the oven and let the pavlova cool still in the oven to 2-4 hours or overnight.
Once the pavlova is fully cooled, remove from baking sheet and plate.
To make the pastry cream:
While the pavlova is baking, make the pastry cream (it will take a while to chill in the fridge). Pour your 2 cups of whole milk into a small saucepan and heat over medium-low, stirring frequently. Once boiling, remove from heat and set aside. In a large bowl, whisk together the egg yolks and sugar until lighter and fluffier, about 2 minutes. Add in the cornstarch and whisk to combine. Slowly add 1/4 cup of the hot milk into the egg yolk mixture, whisking constantly, to temper it. Then continue to slowly poor in the remaining milk until fully incorporated into the yolk mixture. Pour mixture back through a sieve into the saucepan and turn heat back on (med-low) and whisk constantly while it continues to cook. It will thicken suddenly so keep stirring. Once it has thickened, scoop into a smaller bowl, press plastic wrap onto the pastry cream, and chill in the fridge for at least an hour. Once chilled, remove and stir in the jasmine flavor/extract.
To make the whipped cream:
Whisk cream in a medium bowl until soft peaks form. Add in the powdered sugar, and whisk to combine. Use a blender or food processor to blitz up your freeze dried raspberries, until they are a fine powder (and seeds), then pour the powder and seeds through a sieve to remove seeds and add the powder to your cream. Finally, add in the vanilla extract and whisk to combine. If the mixture is too thick to spoon on top of the pavlova, add more unwhipped cream and stir to combine.
To construct:
Place your cooled pavlova on a platter or plate. Scoop the whipped cream on top (do not press down or you'll crush the pavlova), then scoop the pastry cream on top of that. Finally, add any chopped fruit, flowers, etc you want! Serve immediately. While the meringue itself can be made ahead, only decorate the pavlova right before you intend to eat it!