Crumble the cookies and butter, preferably using a small food processor.Then evenly distribute and press the crumbs into 4 baking rings. This works particularly well with a coffee tamper. Place them on a large plate or the base of a large springform pan and refrigerate.In a small saucepan, bring the plant-based milk, coconut blossom sugar, and agar agar to a boil and let it simmer for a minute. Set aside.Whip the vegan cream in a large bowl. Then fold in the skyr, vanilla, Hojicha powder, salt, and the cooked mixture until a light brown cream forms.Heap this mixture onto the crumb layer in the baking rings and place them in the freezer for 2 hours. Now you can carefully remove the rings and sprinkle the mini cheesecakes with more Hojicha powder. You can do this easily with a small sieve and a spoon, gently tapping the sieve.Serve immediately. You can also store them in an airtight container in the refrigerator for a few days, but they will become very soft in texture. They will still taste great though.