Preheat the oven to 160 º C.
Bring the water and sugar over heat until it reaches about 108 º C in temperature.
Add the almond flour and squash jam. Let it boil for a few more minutes, stirring throughout the process.
Remove from the heat and let it cool down a little.
Beat the yolks in a separate bowl, Slowly pour in the sugar syrup, mixing with a whisk so the eggs don't cook.
Bring over medium heat again. Keep stirring until the mixture thickens. It should resemble a pastry cream in texture.
Spread this mixture in a cake pan, previously greased and lined with baking paper, of about 18 cm in diameter.
Bake for about 30 to 35 minutes. A skewer inserted in the center should come out dry.
Let it cool down completely. Dust the top with powdered sugar.