• If you want a sweeter panna cotta, add 1 to 2 tablespoons of sugar to the cream and vanilla mixture as it is heating up. But be sure not to add too much sugar because too much can keep gelatin from setting properly.
• If you want a lemon-flavored white chocolate panna cotta, add the desired amount of lemon zest to the cream and vanilla mixture as it is heating up to allow it to infuse the cream.
• Serve it family-style, chilled in a single large brioche tin or other pie or casserole dish, and let everyone help themselves. No need for unmolding, and it still looks beautiful drizzled with sauce and chopped fruit or nuts. 

How to Substitute Gelatin Sheets in this Recipe

It's always best to use the type of gelatin called for in any given recipe, but sometimes you want to make a recipe and you just don't have gelatin sheets lying around.

You should be able to successfully substitute 1 1/2 teaspoons of powdered gelatin for the sheet gelatin called for.  Although I've not yet tried this particular recipe with powdered gelatin, I believe it should give you just the right delicate panna cotta consistency. Do not use more than 2 teaspoons for 2 cups of liquid, or it may be too firm.

If substituting gelatin sheets with agar agar, use approximately 1.5-2g agar agar powder (1/2 to 3/4 teaspoon) for the 8g gelatin sheets called for in this recipe. Agar is 3-5 times stronger than gelatin. Whisk the agar powder into the cold cream mixture, then bring to a full boil while stirring constantly and simmer for 2-3 minutes to fully dissolve.

Note: Agar sets firmer and more brittle than gelatin, creating a different mouthfeel - it's less creamy and melts at higher temperatures. Again, I have not tested this, but it should give you a good starting point to get the best ratios.