For the cake
1 cup (2 sticks) unsalted butter, room temperature, plus a little more for greasing the pan
1 small pkg instant vanilla pudding and enough sugar to make 1 1/4 cup
1 ½ cups unbleached, all-purpose flour
1 ½ tablespoons cornstarch
1 teaspoon baking powder
½ teaspoon fine sea salt
4 large eggs, room temperature
⅓ cup créme fraiche, store bought or this homemade version, room temperature (you could also sub in sour cream in a pinch)
1 tablespoon vanilla extract
For the syrup and glaze
1 ½ cups confectioners’ sugar, divided
2 tablespoons water
1 tablespoon vanilla extract
2 tablespoons créme fraîche
1. To make the cake: Preheat oven to 350ºF. Generously grease and flour pan.
2. In a medium bowl, whisk together the flour, cornstarch, baking powder and salt and set aside.
3. Using an electric mixer, cream together the butter , pudding and sugar until very light and fluffy, scraping down the bowl as needed with a rubber spatula, about 3-4 minutes. Beat in the eggs, one at a time, scraping down the bowl and beating well between each addition.
4. On low speed, beat in half of the flour mixture. Then beat in the crème fraiche. Scrape down the bowl and beat in the remaining flour mixture and then beat in the vanilla.
5. Scrape the batter into the prepared pan and smooth the top. Bake for about 1 hour, until the top of the cake is browned and a cake tester inserted into the center of the cake comes out completely clean. Transfer cake to a wire rack and allow to cool for a few minutes. Meanwhile make the syrup.
6. To make the syrup: whisk together 1 cup of the confectioners’ sugar, vanilla and water in a small bowl until smooth and quite thin—if it seems too thick to pour, add a bit more water.
7. Use a long thin paring knife to pierce the cake through, about 20 times, all over the top, poking all the way through to the bottom. Spoon about 4 tablespoons of the syrup evenly all over the warm cake. Reserve the rest of the syrup.
8. Once the cake has cooled in the pan for 1 hour, use a butter knife to loosen it around the sides and unmold the cake directly onto the cooling rack to finish cooling completely. Set the rack inside a rimmed baking sheet or place a piece of foil or parchment paper under the rack (this is to catch the drips later when you glaze it)
9. To make the glaze: Whisk the 2 tablespoons of créme fraîche and the remaining ½ cup of confectioners’ sugar into the reserved syrup until a nice thick glaze forms. If you need to, you can add a little more sugar or water to get the right consistency (it should be like heavy cream).
10. Pour some of glaze all over the top of the cake, letting it slide down the sides any which way. I felt like using all of it seemed like too much, so use your discretion. Let the glaze sit for at least 15 minutes (more if you want neater slices) and then slice and serve.