Remove the egg and the butter from the refrigerator (2-3 hours before using it). Cut it into pieces to save at least half the time.
Preheat oven to 350°F (180 °C).
Place almonds on a baking tray and bake them for 10 minutes. Be careful not to burn them. Let them cool.
In a large bowl, beat the butter with a stand mixer or an electric hand mixer on high speed for 15 minutes until white and fluffy.
Add powdered sugar and beat another 10 minutes until it turns white and looks like whipped cream.
Add egg yolk and beat until incorporated for a couple of minutes. Do the same for the rest of the ingredients: cognac or brandy, baking powder, vanilla extract, toasted almonds, rosewater or flower water, or amaretto.
Add the flour gradually with a spatula or big spoon and combine. When the dough is thick enough, use your hands to combine.
Add gradually 5 cups and shape a cookie. If the cookie melts, add a bit more flour to the mixture and shape another cookie. Repeat until the cookie keeps its shape. Don’t overwork the dough.
Shape into thick round cookies, crescents, or balls, place them on a baking sheet lined with parchment paper, and bake for 15-20 minutes in the middle oven rack until lightly golden brown.
Let them cool completely before placing them on a platter. Dust them with a generous amount of powdered sugar using a strainer.