Start by slicing each beetroot as thinly as you can, 2-3 mm thick. Melt the butter in a large frying pan over a low heat and add the uncooked beet slices.
Cut out a circle of non-stick baking paper, roughy the same size as the pan. Scrunch it up, then spread it out again into a crinkled circle (this help trap steam to aid the cooking process). Lay it over the beetroot and allow to steam for 8 minutes or until just soft. Set aside to cool slightly.
Preheat the oven to 200℃ (fan 180℃, 400℉, Gas 6). Roll out the pastry on a lightly floured work surface and roll into a rectangle of roughly 20cm x 30cm and 3 mm thick. Transfer to a baking sheet and score a 2 cm border around the edge using a sharp knife, making sure you don't cut right through the pastry.
Place the mascarpone in a small bowl and stir to loosen it. Mix in the horseradish and season with a little salt and pepper. Spread over the pastry, taking care not to go over the scored border. Top with a mixture of the beetroot slices. Brush each slice with olive oil, sprinkle over the thyme leaves and bake for 30 minutes.
Remove from the oven and allow to cool slightly, then brush with honey just before serving.
For a simpler version, you can do as I did and just go with ready cooked beetroot or boil them yourself.Recipe and image reproduced from Higgidy: The Cookbook by Camilla Stephens. With permission from Octopus Books.Please note: calories and other nutritional information are per serving. They’re approximate and will depend on exact ingredients used.