Preheat the oven to 350°F (175°C). Butter a 9-inch (23 cm) round cake pan (or a 9x5-inch loaf pan) and dust lightly with 1 tablespoon granulated sugar, tapping out the excess.

Dry ingredients

In a medium bowl, whisk together the 2 cups all-purpose flour, 2 teaspoons baking powder, and 1 teaspoon fine sea salt until evenly combined.

Wet ingredients

In a large bowl, whisk 1 cup granulated sugar with the 3 large eggs until slightly thickened and pale (about 1–2 minutes). Add 3 tablespoons extra-virgin olive oil, 3 tablespoons whole milk, 1 cup Greek yogurt, 2 tablespoons lemon zest, 1 tablespoon orange zest, and 2 teaspoons vanilla. Whisk until smooth and homogenous.

Combine batter

Fold the dry ingredients into the wet mixture gently with a spatula until just combined. Do not overmix. The batter should be thick but pourable—if it seems very stiff, add 1 tablespoon milk. Scrape the batter into the prepared pan and smooth the top.

Bake

Bake on the center rack for 35–45 minutes (for round pan) or 45–55 minutes (for loaf) until the top is golden and a toothpick inserted into the center comes out with a few moist crumbs. Rotate the pan halfway through baking for even color.

Cool briefly

Remove cake from oven and let it cool in the pan on a wire rack for 10–15 minutes. Meanwhile prepare the glaze. After 10–15 minutes, invert the cake onto the rack (if using a springform or round pan) or leave in loaf pan if preferred and poke the warm cake all over with a skewer or fork to allow glaze absorption.

Vermouth Citrus Rosemary Glaze

Infuse vermouth

In a small saucepan combine 1 cup dry vermouth and the 2 rosemary sprigs (lightly bruised with the back of a knife to release oils). Bring to a gentle simmer over medium heat and simmer for 4–5 minutes, then remove from heat and let steep for 10 minutes off the heat to intensify rosemary flavor.

Make syrup

Strain the vermouth to remove rosemary sprigs and return the liquid to the saucepan. Add 1 cup granulated sugar and a pinch of salt. Bring to a simmer over medium heat, stirring until the sugar dissolves. Reduce heat to medium-low and simmer gently until the syrup thickens slightly, about 6–8 minutes. Stir in 2 tablespoons lemon juice and 2 tablespoons orange juice. If using, whisk in 1 tablespoon unsalted butter off the heat for a glossy sheen. Allow the glaze to cool slightly (warm, not hot).

Glaze cake

Place the warm cake (still in pan or on rack over a tray) and spoon or brush the warm vermouth glaze evenly over the top, allowing it to soak into the cake. Use all or most of the glaze—reserve 2–3 tablespoons for serving if desired. If the cake cooled too much and glaze thickened, warm the glaze slightly to pourable consistency.

Finish

Set and serve

Let the glazed cake sit at room temperature for at least 30 minutes to allow the syrup to absorb. If desired, dust with 2 teaspoons powdered sugar and garnish with an extra rosemary sprig before slicing. Serve at room temperature. Leftover cake keeps covered in the refrigerator for up to 4 days; bring to room temperature before serving.