To make the beets: Preheat the oven to 400°F. Peel the beets and slice into 1/4-inch (6-mm) slices. Toss with the olive oil and salt. Spread out into a single layer on a sheet tray or two. Roast until tender, 35 to 45 minutes.

Meanwhile, to make the crust: In a food processor, combine the flours and salt. Pulse in the butter/cream cheese until the dough is in slightly larger than pea-size pieces. Pulse in 1 tablespoon of the water, and continue to add water and pulse until dough starts to come together. Remove from the food processor and shape into a disk. Wrap in plastic wrap and refrigerate for 20 minutes.

To make the filling: In a medium bowl, mix together the ricotta, rosemary, salt, garlic, and egg white. On a surface lightly covered with flour, roll the dough out to a 12- to 14-inch (30- to 35.5-cm) circle. Spread the ricotta mixture evenly over the crust, leaving a 2-inch (5-cm) edge. Layer the beets evenly in a circular pattern, covering the ricotta. Fold the edges of the crust over the outer edge of the beets, pleating as needed to make an even circle. (The center of the galette won’t have any dough over it.) Brush the olive oil over the beets. Combine the egg yolk with the heavy cream or water and brush the outer edge of the crust. Bake for 40 to 45 minutes, until the crust is golden brown. Allow to cool slightly and sprinkle with goat cheese and black pepper before serving.