Preheat oven to 375 degrees F/190 degrees C. Place cottage cheese in a large fine-mesh sieve, stainer, or colander lined with a cheese or mesh cloth. Let the excess liquid drain. Meanwhile, grease a 7-inch (18 cm) leakproof springform pan and line it with parchment paper on the bottom and sides.

To make a cookie crust, place crushed cookies with melted butter in a bowl and mix. With the flat bottom of a glass or the back of a tablespoon, press the crust into the bottom of the pan. Set it aside.

To make the cottage cheesecake filling, transfer the drained cottage cheese to a mixing bowl. Add sugar, sour cream, vanilla extract, and eggs, and mix with a hand whisk. Fold in almond flour and gently mix again.

Pour the mixture into the prepared pan and bake for 35-40 minutes. Take it from the oven and let it cool down to room temperature for a couple of hours. Or chill the cheesecake in the refrigerator for 2-4 hours.

To make blackberry sauce, place blackberries with 1 tablespoon of water in a heavy-bottomed saucepan. Cover it with a lid, and cook over low-medium heat for about 7-8 minutes. Blackberries will fall apart and release juice.

In a small bowl, mix cornstarch, sugar, and 1 tablespoon of water. Remove the cooked blackberries from the heat, and add the cornstarch mixture, stirring constantly.

Bring the saucepan to heat and cook, frequently stirring, on low for about 5 minutes until the sauce thickens. If it seems too thick, add 1-2 tablespoons of water, mix, and heat again. Pass the sauce through a fine-mesh sieve and discard the berries.

To serve, spoon the blackberry sauce over the individual slices and decorate with fresh blackberries.