Actually, as things go nowadays, panna cotta is probably one of the cheapest deserts you can make.
The most expensive item would be the 1 3/4 cups cream this recipe calls for, followed by the bananas. But it makes eight servings, which brings the cost per down to mere pennies.
If anyone cares, it's one of the great recipes in Camilla Saulsbury's wonderfull little Panna Cotta Italy's Elegant Custard Made Easy. There are about a hundred versions, both sweet and savory. Here's the one I made last night:
Banana Panna Cotta with Caramel-Pecan Drizzle
4 ripe, large bananas, peeled
2 tsp fresh lemon juice
3/4 cup banana flavored schnapps or water
2 tsp unflavored gelatin
1 3/4 cups heavy whipping cream
1/4 cup sugar
1 tsp vanilla extract
1/2 tsp ground nutmeg
1 recipe Caramel-Pecan Drizzle
Place the banana in a blender or food processor. Puree until very smooth. Measure 1 2/3 cups banana puree into a 2-cup glass measure cup; mix in lemon juice and set aside (save any extra banana puree for another use)
Place schnapps or water in small bowl. Sprinkle gelatin over. Let stand 5 minutes to soften gelatin.
Bring the cream and sugar to simmer in heavy, medium saucepan set over medium-high heat, stirring until sugar dissolves. Remove from heat. Add gelatin mixture and whisk until dissolved. Whisk in the banana puree, vanilla, and nutmeg until blended.
Ladle or pour mixture into 8 3/4-cup custard cups, ramekins, or small molds. Loosely cover with plastic wrap and chill 4 hours or up to overnight.
Unmond each panna cota onto a plate. Spoon the caramel pecan drizzle around each.
Caramel-Pecan Drizzle
1 cup premium caramel sauce
2/3 cup pecans, coarsely choped and lightly toasted
In a medium saucepan set over moderately-low heat, heat the caramel sauce with the recans, stirring until warm but not hot.