Preheat oven to 350°F / 175°C. Line a 9-inch pan with parchment and lightly oil the sides.
For the caramel:
In a saucepan, combine 100g granulated sugar and 25g water. Cook over medium heat without stirring, watching closely as it turns from clear to pale gold to a deep amber quickly. You're looking for a rich amber color and a light caramel aroma. Remove from heat and carefully add 1–2 oz (30–60 ml) bourbon. It will bubble and may seize slightly, which is normal. Return to low heat and whisk continuously until the caramel fully smooths out again. Add 40g butter and whisk until glossy and emulsified. Immediately pour into the prepared pan and tilt to evenly coat the bottom. Lay the 2 blood orange slices in a slightly overlapping layer.
For the Olive Oil Cake:
In a large bowl, add 150g eggs, 160g granulated sugar, 40g light brown sugar, ¾–1 tsp freshly ground cardamom, and zest of 2 oranges. Whisk vigorously for 3–5 minutes until pale and slightly thickened. Add the wet ingredients: 120 ml olive oil, 80 ml orange juice, 1 oz (30 ml) bourbon, and 1 tsp vanilla extract, and whisk to combine. In a separate bowl, whisk together 190g all-purpose flour, 1½ tsp baking powder, and ½ tsp kosher salt. Add the dry ingredients to the wet batter and whisk until just smooth. Pour batter gently over the oranges in the prepared pan.
Bake for 30–40 minutes, until the top is golden, the center springs back lightly, and a toothpick comes out clean or with a few moist crumbs. Let the cake cool for 5 minutes. Run a knife around the edges. Invert the cake onto a wire rack and sheet tray. Flip while still warm—this helps the caramel release cleanly. Allow to cool completely before slicing. Serve with vanilla ice cream or a cafecito.
