In a medium bowl, whisk together flour, sugar, sea salt, cardamom, and vanilla bean. Add diced butter, and mix into dry ingredients using your fingertips or a pastry cutter, just until butter is in pea-sized pieces and beginning to make the mix a bit sandy looking. Add egg yolks and continue to mix until dough comes together and has a sandy texture. Divide into two pieces and pat into even 5" rounds. Wrap in plastic and refrigerate for an hour.
While you wait, get out your muffin tins. I used regular sized non-stick muffin tins, which easily released the tart shells without any extra greasing. The recipe is ideally intended for mini-muffin tins, but it worked just fine with full-size.
After an hour, remove disks of dough from fridge and preheat oven to 400º. On a lightly floured surface, roll out disks of dough one at a time to ¼" thickness. Use a 3" cookie cutter (or a 3" diameter water glass, like I did!) to cut 16 circles total. Transfer each circle immediately to the base of a muffin tin, gently pressing to ensure even contact with the bottom and sides of the pan. Feel free to consolidate and re-roll dough as you go, but remember that the closer to room temp it gets, the more difficult it is to work with!
Bake for 18-22 minutes, until just golden brown. Remove from oven and let rest on a cooling rack at least 15 minutes. Then lift tart crusts from pan and leave them to cool further on the rack.
While they cool, gently swirl a tablespoon of honey into one cup of Greek yogurt and leave in fridge until ready to fill tarts. I like leaving a few ribbons of honey in the yogurt as opposed to fully mixing it in. Slice figs and nectarines into thin wedges and slices, respectively.
Remove yogurt honey blend from fridge and spoon evenly into tart shells. Garnish with a few figs and a couple nectarine slices on each tart. Add mint leaves liberally—the fruit tastes so good with pops of cooling mint.
Finally, drizzle lightly with olive oil and add a tiny sprinkle of sea salt on each. Let set in the fridge for 30 minutes, and serve immediately!