Adjust oven rack to middle position and preheat oven to 325°F (165°C) if using a glass 9- by 13-inch ceramic or glass baking dish or 350°F (175°C) if using a metal one. Generously butter baking dish and set aside.

Using a mortar and pestle or spice grinder, lightly crush cardamom pods. Remove and discard shells, then grind seeds into a coarse powder.

In a large bowl, whisk together all-purpose flour, almond flour, baking powder, salt, and ground cardamom. Set aside.

In a large bowl with an electric hand mixer, or in the bowl of a stand mixer fitted with a whisk attachment, beat egg whites on medium speed until foamy, about 1 minute. With the mixer running, gradually add ¼ cup (50 g) sugar and continue beating until stiff peaks form, about 3 minutes longer. Set aside.

In a third large bowl, add egg yolks and remaining 1 cup (200 g) sugar and whisk until mixture is pale yellow and slightly thickened, 2 to 3 minutes. Whisk in milk and vanilla until combined.

Add egg yolk mixture to flour mixture and stir just until no dry pockets remain. Using a flexible spatula, gently fold beaten egg whites into batter in three additions just until fully incorporated and no white streaks remain.

Scrape batter into prepared baking dish or pan and spread into an even layer. Bake until cake is golden, and a toothpick or cake tester inserted into the center comes out with a few moist crumbs attached, 25 to 30 minutes. Transfer baking dish or pan to a wire rack and let cake cool completely, about 1 ½ hours.

Meanwhile, in a medium saucepan, combine sweetened condensed milk, coconut milk, and whole milk. Finely crush saffron threads in a mortar and pestle or finely chop with a knife, then add to saucepan with milk. Cook over low heat, stirring occasionally, until mixture is warmed through and evenly combined, about 5 minutes. Do not let mixture boil.

Using a skewer or toothpick, poke holes all over cooled cake all the way down to the base, making sure to evenly poke the corners of cake. Slowly pour leche mixture evenly over cake. Cover and refrigerate for at least 3 hours or up to 24 hours.

When ready to serve, in a large bowl with an electric hand mixer, or in the bowl of a stand mixer fitted with a whisk attachment, combine heavy cream and powdered sugar. Beat on medium speed until medium peaks form, 1 to 3 minutes.

Spread whipped cream evenly over cake. Using the back of a spoon, create decorative swoops and swirls, if desired. Sprinkle with crushed pistachios. Let cake stand at room temperature for 15 to 30 minutes before serving.