Frangipane is a delicious filling made with ground almonds (almond powder) 

For the frangipane filling: 
100g (1/2 cup) icing sugar (powdered sugar, though you can use regular)
120g ground almonds (almond powder or flour)
100g (7 tablespoons) unsalted butter, softened but not melted
2 eggs, room temp (save 1/2 of egg yolk for glaze)
1/8 tsp almond extract 
zest of an orange
2 teaspoon rum (option but yummy!)

+ puff pastry 

+ glaze - 1/2 of egg yolk (from above) + a little milk

+ a little "feve" or prize - a tiny ceramic (heat proof) toy 

Mix all the above together - dry ingredients first then add eggs and flavorings. It will be grainy and thick. Spread it between two layers of puff pastry leaving about 1/2 - 1" from the edge - cut to about the size of a small pie. Brush a little water around the edge of bottom pastry to adhere the top.
DON'T FORGET TO add a little feve or prize in it before placing the top layer. Press the edges together and lightly cut slits or decor on the top. You can scallop the edges how you want. 
Brush with egg yolk/ milk mixture and back at 375 degrees for about 30 minutes until golden.
If the galette puffs up too much during cooking, cut a couple slits into the top. 

VOILA!