Spain here colonizes the chayote with typically peninsular ingredients such as ground almonds and by making a flan with its processed flesh.
4 large chayotes, sliced in half lengthwise
Peel of 1lemon
Bring 8cups of lightly salted water to a boil. Add the chayote halves, return to the boil, reduce the heat, and simmer until tender, 20 to 30 minutes.
Drain the chayotes. As soon as they are cool enough to handle, spoon out the flesh and reserve, being careful not to damage the peels. Discard the seeds.
Dissolve the cornstarch in the milk. Pour into the processor and add the chayote flesh and process until smooth. Transfer to a saucepan. Add the stick of cinnamon, the lemon peel, the egg yolks, and the sugar. Stir together and heat over medium heat until the custard thickens. Remove from the heat and immerse the pan in cold water to stop the cooking. Stir to cool for a couple of minutes. Remove the cinnamon stick and the lemon peel and discard.
Stir in the vanilla and the raisins. Spoon this mixture into the chayote peels (put any excess in a serving bowl). Chill for several hours before serving. Meanwhile, toast the ground almonds in a 300-degree oven until lightly browned. When ready to serve, sprinkle the custard with the almonds.