Place a mixing bowl and your mixer's whisk or beaters in the refrigerator to chill
disolve the gelatin in the 2 tbsp of room-temperature water and set aside while it blooms
Finely chop the white chocolate and place it in a large mixing bowl (about 2 quart).
Puree the raspberries in a blender or food processor
Strain the pureed berries through a fine mish sieve to get rid of the seeds. You'll have to push the pureed mixture against the sieve to squeeze out as mucn of the juice as possible. It's ok if a few seeds leak through, too. Note the recipes quantities are before the seeds are squeezed out; you'll wind up with a bit less raspberry for the actual ingredient.
Place the raspberries, sugar, and lemon juice in a small saucepan and bring to a gentle simmer while whisking. Let simmer about five minutes--this releases the natural pectins in the berries.
Remove the berries from the burner and add the now-bloomed gelatin to the berries and whisk until disolved and thorougly mixed. The heat from the berries will help disolve the gelatin.
Pour the still-hot raspberry mixture over the white chocolate. Make sure the berry mixture covers the chocolate. Let it sit for a minute or two while the white chocolate softens, then whisk the mixture until completely blended. Don't let this sit for more than five minutes or so before you begin to blend it with the whipped cream, or the gelatin will start to set up and interfere with the blending.
Next, put the heavy cream in the bowl that's been chilling in the refrigerator and beat it to soft peaks. This takes roughly than two minutes with my Kitchenaide stand mixer and the whisk. Do not beat to hard peaks.
Put about a third of the whipped cream in the bowl with the berry/white chocolate mixture and fold them together. This will both cool the mixture and prime it for folding the remaining cream.
Finally, add the rest of the whipped cream into the bowl and gently fold the mixture together until there are no white streaks. Well, it's ok if there are a few white streaks--they can even add to the appearance.
Cover with plastic wrap and refrigeratorate for at least two hours and preferably overnight.