Herbed Red Potato and Caramelized Onion Tarts

Steps

1. Make the crust first: whisk the whole wheat flour, the all-purpose flour, half the rosemary, half the thyme and 4 g of the salt in a bowl to make the dry mix.
2. Rub the butter into the dry mix until pea-sized pieces remain, then drizzle in the water and toss just until the dough holds together.
3. Divide the dough in half, flatten each half into a disk, wrap and chill for 1 hour.
4. While the dough chills, warm two-thirds of the olive oil in a skillet over medium-low heat, add the onion and 1 g of the salt and cook, stirring often, for 30 minutes until deep golden; stir in the garlic for 1 minute, then let cool.
5. In a bowl, toss the potato with the remaining one-third of the olive oil, the remaining half of the rosemary, 1 g of the salt and half the black pepper.
6. Make the herb spread: stir together the ricotta, feta, half the parsley, the remaining half of the thyme, the remaining 1 g of salt, the remaining half of the black pepper and the egg.
7. Preheat the oven to 400°F (200°C). Roll each dough disk into an 11-inch round, fit into two 9-inch tart pans, trim the edges and chill 15 minutes.
8. Spread half the herb spread in each crust, top each with half the caramelized onion, then shingle half the seasoned potato slices over each in overlapping circles.
9. Bake for 45 to 50 minutes, until the crust is deep golden, the potatoes are tender when pierced and the filling reaches 160°F (71°C).
10. Cool the tarts on a rack for 20 minutes, scatter the remaining half of the parsley over both, and cut each tart into 6 slices.