Make the cakes. Oil the bottom and sides of 2 9-inch round cake pans. Cut 2 9-inch parchment circles and lay in the pans. Turn on the oven to 350 degrees and adjust a shelf to the middle.
In a medium bowl whisk together the flour, baking powder and salt. Separate the eggs, putting the whites into the bowl of your mixer, the yolks into another medium bowl. Whisk the oil, water and half (1/2 cup plus 1 tablespoon/125 g) the sugar into the yolks. With the whisk attachment, beat the whites with the cream of tartar on medium speed until foamy. Increase the speed to medium-high and, when the whites look like they will hold soft peaks, add the second half of the sugar 1 tablespoon at a time, beating for about 30 seconds after each addition. Once all the sugar is incorporated, continue beating for another minute or so, until the egg whites are nearly stiff. Whisk the dry ingredients into the egg yolk mixture until thoroughly incorporated, then gently stir in about ¼ of the whites to lighten the batter. In 2 additions, carefully fold in the remaining egg whites, folding just until there are no visible streaks of white.
Divide the batter between the two pans, slide into the oven and bake until lightly golden and springy to the touch (a toothpick inserted near the middle should come out clean), about 22 to 25 minutes. Cool 10 minutes, then run a thin knife around the edge of both pans and turn the cakes out onto cooling racks. Cool to room temperature, about 30 minutes.
Make the Tres Leches. In a bowl or blender jar, combine the evaporated, sweetened condensed and whole milk with the vanilla. Whisk or process until thoroughly combined.
Finish the cake. With your electric mixer, beat the cream (adding a few tablespoons of sugar if you wish) until it forms stiff peaks. Have the fruit at easy access. Place one of the cake layers on a serving plate and poke 20 or 30 holes in it with a skewer or large fork. Slowly and evenly start spooning the tres leches liquid over the entire surface of the cake (don’t miss the edges), letting one spoonful be absorbed before adding the next. It will take about 4 or 5 minutes for the cake to absorb about half the liquid, but if you notice any liquid seeping out at the bottom, stop adding more; the cake has absorbed its max. Spread about 1 cup of whipped cream over the cake, then top with a little less than half the fruit, pressing the fruit into the cream. Lay the second cake on top, gently press it to compact the filling and, if necessary. to level it. Poke holes in the cake, then slowly spoon on the remaining liquid.
Frost the sides and top of the cake with the remaining whipped cream. Pile on the remaining fruit and refrigerate your beautiful creation until you’re ready to serve.