Make sure your cream cheese is truly room-temperature (assuming a kitchen temperature of 65-70 F).
If using freeze-dried raspberries, place in a clean spice grinder and pulse to grind into a fine powder. Sift the raspberry powder into a medium-sized bowl to remove the dried raspberries seeds. Sift the powdered sugar into the same bowl. Add the salt to the bowl, then whisk gently to combine.
In a stand mixer with the paddle attachment, beat the cream cheese on medium speed until smooth, about 1-2 minutes. Add the sifted dry ingredients, food coloring (if using), vanilla bean seeds, and vanilla extract to the beaten cream cheese. Beat on medium speed until light and completely smooth, about 3 minutes. Do not short-change the time you give to this step - the frosting should visibly thicken and lighten in color during this time.
Scrape down the bowl and replace the paddle attachment with a whisk. With the mixer running on low, add the cream very slowly, pausing every 5-10 seconds to scrape down the bowl, until it is fully combined. Increase the speed to medium high and whisk until stiff peaks form, scraping down the bowl as necessary (at least several times), about 2-3 minutes total.
To assemble the cake, place one layer of the yellow cake on a serving platter. Top with a generous 1 cup of the whipped cream frosting (or half the frosting if you’re making a naked cake). Spread evenly over the surface, then dot about ½ the raspberries on top of the frosting.
Cover with the remaining cake layer. Frost the top and sides (or just the top as I did) with the remaining whipped cream frosting. Dot the surface with the remaining raspberries.
Serve immediately or chill for up to 12-18 hours prior to serving.