Brush beets clean. Place on a cookie sheet lined with aluminum foil. Rub all over with olive oil. Roast in a 400° oven for 1 hour until cooked all the way through. Once cooked allow to cool for about 5 to 10 minutes, then peel while still warm. Carefully, slice beets into 1/8 inch thick rounds.
Measure out the flour and place in a food processor.
Cut butter into cubes and add to the flour…
Add salt then run the food processor until the mixture turns into coarse meal. Add egg yolk and 3 tablespoons of cold water. Process again until the dough comes together and forms into a ball.