To begin, preheat your oven to 200°C (fan 180°C). In a large bowl, combine rye flour, plain flour, sugar, and salt. Add softened butter and rub it in using your fingertips until the texture is sandy. Gradually add water and knead lightly to form a firm dough. Wrap and chill for 20 minutes.

While the dough rests, prepare the potato layer. Boil the chopped potatoes in salted water until soft, about 15 minutes. Drain and mash while hot with butter and a pinch of salt. Avoid over-mashing to prevent a gummy texture. Set aside to cool slightly.

In a separate pot, boil carrots until tender, about 12 to 15 minutes. Drain and mash thoroughly. Let cool slightly before adding egg, sour cream, sugar, cinnamon, nutmeg, and a pinch of salt. Stir until smooth and lightly spiced.

Retrieve the dough from the fridge and divide it into 8 equal pieces. Roll each piece into a thin disc, approximately 8cm in diameter. The edges do not need to be perfectly round; rustic shapes are traditional.

Fold the edges of each disc upward to form a shallow tart shell with an open centre. Pinch the sides gently to keep them in place. These edges should be about 1 to 1.5cm high to contain the fillings.

Line a baking sheet with parchment paper. Place the rye shells onto the sheet, spacing them evenly. Spoon a thin layer of mashed potatoes into each shell, pressing gently to fill the base.

Top each tart with a generous spoonful of the carrot mixture. Smooth the surface with the back of a spoon. Do not overfill, as the mixture may spill during baking.

Transfer the baking tray to the oven and bake for 30 to 35 minutes until the edges of the crust are firm and the filling is set. The carrot top should be slightly puffed and just beginning to colour.

Allow the tarts to cool slightly before serving. Sklandrausis is best enjoyed warm or at room temperature with a spoonful of sour cream. For presentation, serve on a wooden board or rustic plate to reflect its countryside origins.