Instructions

1. Cut 1 stick unsalted butter into small cubes and place in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Place 2 large eggs and 2/3 cup whole milk on the counter and let everything sit at room temperature until the butter is softened.
2. Coat an 8-inch round cake pan (2-inches high) with cooking spray. Line the bottom with a parchment paper round, then line the sides with a 3-inch wide strip of parchment paper to form a collar that extends up above the top of the pan. Pour 3 cups water into the pot of the Ninja® Foodi® XL Pressure Cooker Steam Fryer with SmartLid™.
3. Place 1 cup all-purpose flour, 3/4 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon kosher salt in a medium bowl and whisk to combine.
4. Finely grate the zest of 1 large lime (about 2 teaspoons) and 1 large lemon (about 1 tablespoon). Juice the limes until you have 1 tablespoon juice.
5. Add the lime juice and 1 teaspoon lemon extract to the milk and stir to combine. (The mixture may thicken or curdle.)
6. Add the zests and 3/4 cup granulated sugar to the bowl of butter. Beat with the paddle attachment on medium speed until light and fluffy, about 3 minutes. Beat in the eggs one at a time, waiting until each egg is completely incorporated before adding the next. Scrape down the sides of the bowl with a flexible spatula.
7. Turn the mixer to the lowest speed. Gradually add in 1/2 of the flour mixture, stopping and scraping down the sides of the bowl as needed. Add 1/2 of the milk mixture and beat until combined. Repeat beating in the remaining flour and milk mixtures. Increase the speed to medium and beat until light and smooth, about 15 seconds. Transfer the batter into the pan and spread into an even layer.
8. Place the pan on the bottom layer of the Deluxe Reversible Rack in the lower position, then place the rack in the pot. Close the lid, move slider to STEAMCRISP, and turn knob to select STEAM & BAKE. Turn pressure valve on lid to SEAL or VENT (the position does not matter in this mode). Set temperature to 285°F and set time to 25 minutes. Press START to begin cooking. It will steam for about 20 minutes and display PrE, then the timer will start counting down.
9. When the cooking time is complete, open the lid. A toothpick inserted into the center of the cake should come out clean and the center of the cake should spring back when lightly pressed. (If the cake is not ready, close the lid, select STEAM & BAKE, and cook at 285ºF for 2 minutes more.) Remove the rack with the pan and let the cake cool for 10 minutes. Flip the cake out of the pan and cool completely on the rack, about 1 1/2 hours more.
10. If desired, trim the top of the cake with a serrated knife to even the top out. Cut the cake horizontally in half to make 2 layers. Spread 3/4 cup lemon or lime curd on the bottom half of the cake. Replace the top half.
11. Just before serving, place 2 cups cold heavy cream, 1/4 cup granulated sugar, and 1 teaspoon vanilla extract in a stand mixer fitted with the whisk attachment. (Alternatively, use an electric hand mixer or whisk by hand in a large bowl.) Beat on medium speed until firm peaks form, 2 1/2 to 3 minutes. Pile the whipped cream onto the top of the cake and use the back of a large spoon or an offset spatula to frost the top and sides of the cake.