Ingredients

Unsalted butter, for the pan

1/2 cup firmly packed (90 g) light or dark brown sugar, or granulated sugar

2 Tbsp water

2 oranges, very thinly sliced

1/2 cup (110 g) unsalted butter, at room temperature (for step 3)

3/4 cup (150 g) granulated sugar (for step 3)

3 large eggs, separated (egg whites reserved for the next step)

3/4 cup/180g Ricotta Cheese (homemade or store-bought)

Finely grated zest and juice of 3 lemons 1 tsp sea salt

1/3 cup plus 1 Tbsp/55g stone-ground cornmeal

1 cup plus 1 Tbsp/130g almond flour

Instructions

1. Preheat the oven to 325°F/165°C. Line the bottom of a 10-in/25cm springform pan with 3-in/7.5cm sides with parchment paper cut to fit exactly. Butter the sides of the pan.
2. In a small bowl, mix the brown sugar or granulated sugar and water together to form a paste and then spread it across the bottom of the pan. Arrange the orange slices on top of the sugar paste, overlapping them with one in the center. Try to cover as much of the bottom of the pan as possible; the slices will shrink slightly during baking.
3. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium-high speed until light and creamy, about 1 minute.
4. Add the yolks one at a time to the butter mixture beating well after each addition. Add the ricotta, lemon zest, lemon juice, and salt. Beat to combine.
5. Mix the cornmeal and almond flour into the egg-ricotta mixture. Stop the mixer and scrape down the sides of the bowl with a rubber spatula.
6. In another bowl, whisk the reserved egg whites to soft peaks. Using a rubber spatula, gently fold the beaten whites into the cake batter just until no white streaks are visible. (The batter will be very thick.) Immediately turn the batter into the prepared pan, smoothing the top with a spatula.
7. Bake for 30 to 45 minutes, until the top of the cake is no longer shiny. Let the cake cool in the pan on a wire rack for 15 minutes. To unmold, run a butter knife around the sides of the pan to loosen the cake and then release and lift off the pan sides. Invert the cake, remove the pan bottom, peel off the parchment, and serve.
8. The cake will keep, well wrapped, for up to 4 days at room temperature or about 1 week in the refrigerator.