Preheat the oven to 350°F (177°C). Generously butter and flour a 10–12 cup (2.4–2.8 liter) Bundt pan, taking care to coat all crevices thoroughly.
In a medium bowl, whisk together the all-purpose flour, finely ground almonds, baking powder, and salt. Set aside.
2⅓ cups (290 g) all-purpose flour, ½ cup (50 g) finely ground almonds, 2 tsps (8 g) baking powder, ½ tsp (3 g) salt
In a large mixing bowl, beat the softened butter with the granulated sugar and light brown sugar until pale and fluffy, about 2 to 3 minutes. With the mixer running, slowly drizzle in the olive oil, allowing it to fully emulsify into the butter mixture.
½ cup (113 g) unsalted butter, ¾ cup (150 g) granulated sugar, ½ cup (120 ml) extra-virgin olive oil, ¼ cup (50 g) packed light brown sugar
Add the eggs one at a time, beating well after each addition and scraping down the bowl as needed. Mix in the orange zest, lemon zest, orange juice, milk, Amaretto, and vanilla extract until fully combined.
4 large eggs, 1 tbsp (6 g) orange zest, 1 tbsp (6 g) lemon zest, ¼ cup (60 ml) fresh orange juice, ⅛ cup (30 ml) milk, 3 tbsps (45 ml) Amaretto , 1 tsp (5 ml) vanilla extract
Gently fold the dry ingredients into the batter just until no dry streaks remain, taking care not to overmix. Spoon the batter into the prepared Bundt pan and smooth the top evenly.
Bake for 45 to 55 minutes, until the cake is deeply golden and a skewer inserted into the center comes out clean.
While the cake bakes, prepare the syrup. In a small saucepan, combine the water and sugar and heat over medium heat, stirring until the sugar has completely dissolved. Remove from the heat and stir in the orange juice, Amaretto, Cointreau, and Angostura bitters, if using. Set aside.
½ cup (120 ml) filtered water, ½ cup (100 g) granulated sugar, 2 tbsps (30 ml) fresh orange juice, 2 tbsps (30 ml) Amaretto, 2 tbsps (30 ml) Cointreau, 2 drops Angostura bitters
Allow the cake to cool in the pan for 10 minutes, then use a skewer to poke deep holes evenly across the surface. Slowly spoon most of the warm syrup over the cake, allowing it to absorb gradually.
Let the cake cool for an additional 10 minutes, then carefully turn it out onto a wire rack set over a baking sheet. Brush the remaining syrup evenly over the surface of the cake. Allow the cake to cool completely before transferring to a serving plate or cake stand.
Slice and serve at room temperature. It's better the next day if you can wait.