FOR THE SHEET PAN SHORTCAKE

1. Adjust oven rack to lower middle position; heat oven to 200c/400f degrees.
2. Prepare a half sheet pan by greasing it all over with some butter
3. Mix flour, salt, baking powder, and sugar in medium bowl.
4. Using the large holes of a box grater, grate butter into the dry ingredients. Toss butter with flour to coat. Use pastry cutter (or a fork) to finish cutting butter into the flour. Or scoop up coated butter with both hands, then quickly rub butter into dry ingredients with fingertips until most of butter pieces are the size of split peas.
5. Mix beaten egg with Greek yogurt & milk; pour into flour mixture. Toss with fork until large clumps form.
6. Transfer the dough to the prepared pan and press into an even layer (you can lightly moisten your hands if necessary), the pressed dough should be about 3/4 inch thick.
7. Brush dough with heavy cream and sprinkle with turbinado sugar. (Can be covered and refrigerated up to 2 hours before baking.)
8. Bake until golden brown, about 15 minutes. Place baking sheet on wire rack; cool shortcake until room temperature.

FOR THE ROASTED PLUMS

1. Preheat the oven to 350°
2. Line a half sheet pan with parchment paper, making sure the paper goes up the edges of the pan.
3. Quarter your plums and place them in a bowl. Toss the plums with honey, lemon zest & juice, and vanilla extract if using. Pour plums onto the prepared sheet pan and place cinnamon sticks and cardamom pods here and there about the plums.
4. Roast the plums for 20 to 25 minutes, turning once, until just softened. Let the plums cool in their syrup, then discard the cinnamon sticks and cardamom. Reserve until serving.

FOR THE GREEK YOGURT WHIPPED CREAM

1. Chill a non-reactive, deep bowl and beaters mixer in freezer for at least 20 minutes.
2. Add cream to the chilled bowl; sift in powdered sugar and beat on low speed until small bubbles form, about 30 seconds. Increase speed to medium; continue beating until beaters leave a trail, about 30 seconds more. Increase speed to high; continue beating until cream is smooth, thick, and nearly doubled in volume, about 20 seconds for soft peaks.
3. Add in the Greek yogurt and whip for another ten seconds or so, until whipped cream is thick. If necessary, finish beating by hand to adjust consistency. Keep chilled until ready to serve

TO SERVE

1. Spoon the chilled Greek yogurt whipped cream evenly on top of the cooled shortcake. Using your spoon to create swoops in the cream.
2. Carefully disperse the roasted plums on top of the cream and finish by drizzling the roasted plum juice over the plums.
3. Slice and serve – this shortcake is best eaten within the first 2 hours. Any leftovers should be covered and stored in the refrigerator.