Preheat the oven to 200° Celsius.
Line a baking tray with baking paper and place the first package of puff pastry on the tray. Remove excess dough and use elsewhere (see notes). Prick bottom of galette several times with a fork. In the meantime, place the cake tray in the refrigerator.
Place margarine, sugar and vanilla sugar in a bowl. Using a food processor with whisk attachment, beat mixture until creamy. The mixture will take on a creamy consistency and slightly less yellow color. Alternatively, you can use a whisk.
Add almond flour, starch, salt, and 2-3 drops of bitter almond flavoring.
Now add 200g of vegetable milk and mix the mixture with a pastry spatula. If the filling is still not creamy enough, gradually add a little more plant milk. The amounts of liquid vary depending on the type of almond flour. The filling should be moist - creamy, but still compact and not runny or liquid.
Taste filling and add more bitter almond flavoring drop by drop if necessary. Depending on how intense the flavor is preferred. I like it rather intense, but for some 2-3 drops may be enough.
Spread filling on pie crust with a pastry spatula and smooth it out.
Place second puff pastry on top of filling. Remove excess pastry and press edges of pastry well together with bottom pastry. So that the galette is tightly sealed.
Using a sharp knife, score a spiral pattern on the top pastry. If you like, you can also choose a different pattern. Then, using a brush, brush the top of the dough with soy cream.
Bake the galette for 20 minutes on the lowest rack of the oven so that the bottom is well baked and not mushy soft.
After 20 minutes, move the galette to the second highest rack of the oven and bake again for about 20 minutes. The galette should be baked until golden brown on top, but not burnt.