To make the panna cotta:
Freeze 6 to 8 straight-sided glasses, no bigger than 8 ounces.
In a saucepan, over medium heat, bring the cream, sweetened condensed milk, vanilla bean, sugar and pinch of salt just to a simmer. Turn off the heat and allow the vanilla bean to steep for at least 10 minutes. Pour half the cream/vanilla mixture into another sauce pot.
To one of the pots of cream add the espresso powder (or beans) and cocoa powder. Heat to a simmer and whisk until the powder has dissolved. (If you are using the beans, turn off the heat and allow to steep for about 20 minutes.)
If you are using the beans, strain the coffee beans and then return the coffee cream mixture to the sauce pot.
In two separate bowls, add 2 teaspoons of the gelatin, plus 2 tablespoons cold water. Allow to sit and bloom for 5 minutes. Be sure that all the gelatin powder is submerged in the water. If there is any dry gelatin left in the bowl, sprinkle some water over it.
Once the gelatin has bloomed for 5 minutes put the bowl over a double boiler and melt the gelatin.
Whisk the gelatin gently into the vanilla cream, then pour the panna cotta into a measuring cup or pitcher, cover with plastic wrap and refrigerate to cool. Check the panna cotta after about 20 minutes, to make sure it is thickening, but still pourable. If it is setting up too quickly, bring it to room temperature.
Melt the second bowl of gelatin and then gently whisk it into the coffee cream mixture. Pour the coffee panna cotta into a measuring cup or pitcher, cover with plastic wrap and refrigerate to cool. Check the panna cotta after about 20 minutes, to make sure it is thickening, but still pourable. If it is setting up too quickly, bring it to room temperature.
Once the vanilla panna cotta is starting to thicken slightly, slowly pour some into the prepared glasses. You determine how thick or thin you want the layers. Stick the glasses back into the freezer for about 5 minutes, or just until the vanilla layer is set.
As soon as the vanilla cream is set, slowly pour the coffee layer over it. Freeze the glasses until this layer is set, about 5 minutes.
Continue until you have used up all the vanilla and coffee panna cotta. Let them set for about an hour.
You can serve them just like this, or you can add a thin layer of the espresso gelee to the mix. I like the extra shot of coffee to contrast to the sweet of the panna cotta layers.
To make the espresso gelee:
In a small sauce pan mix together the espresso and sugar. In a small bowl bloom the gelatin, just as you did for the panna cotta, then melt it and add it to the hot espresso. Refrigerate the gelee until just cool, but still pourable.
Pour a thin layer over the panna cotta and allow it to set. Serve it chilled. This can be made up to two days in advance.