For the Orange Cardamom Mini Olive Oil Cakes:

1. Preheat the oven to 350°F.
2. In a large bowl, combine the sugar, orange zest, and lemon zest. Rub the zest into the sugar with your fingers until fragrant.
3. Whisk in the cardamom, orange juice, buttermilk, and vanilla until smooth. Add the eggs and olive oil and whisk until fully combined.
4. In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
5. Add the dry ingredients to the wet ingredients and gently fold until smooth and no flour streaks remain. Do not overmix.
6. Grease an aluminum muffin tin or mini bundt pan well with butter and fill each cavity with about ¼ cup (55 g) of batter.
7. Bake for 18–20 minutes, or until the tops are lightly golden and a toothpick inserted into the center comes out clean.
8. Allow the muffins to cool in the pan for 10 minutes, then carefully invert the pan to release them. Turn the muffins bottom side up and let them cool for at least 10 more minutes before glazing.
9. While the muffins bake, prepare the glaze. In a bowl, whisk together the powdered sugar, melted butter, milk, orange juice, orange zest, and vanilla until smooth. The glaze should be the consistency of maple syrup.
10. Once the muffins have cooled, dip the bottoms (now the tops) of the muffins into the glaze, coating them about halfway up. Transfer to a wire rack to allow the glaze to set, about 10 minutes.
11. Serve immediately, or store in an airtight container at room temperature for up to 2 days, or in the refrigerator for up to 1 week.