Pour the flours, sugar, salt and yeast into a bowl. Add the melted butter, mix with a spoon until you obtain a coarsely crumbly mixture, then pour everything onto a baking sheet and bake at 170° for 25 minutes or until the crumbs are golden and crunchy. Remove from the oven and leave to cool.
Prepare the ricotta mousse: mix the ricotta with the sugar and the grated lime peel until you get a smooth cream. Squeeze half a lemon and the lime, bring the juice to the boil together with the agar, let it boil for 20 seconds, turn off the heat, let it cool and add it to the ricotta cream. Finally, whip the cream and gently incorporate it into the rest of the mixture.
To serve: place two spoonfuls of crumbs at the bottom of a glass, add two or three spoonfuls of ricotta mousse, a spoonful of Amarena Fabbri, cover with another two spoonfuls of ricotta mousse. Keep outdoors until ready to serve.