Preheat oven to 340°F or 170°C. Line the bottom of your pan with parchment paper and brush sides with butter.
To a large mixing bowl, add the dry ingredients: flour, sugar, bakingpowder, and salt. Whisk to combine.
To a second bowl,add wet ingredients: water, oil, and vanilla extract. Whisk to combine.
Pour wet ingredients into dry ingredients and whisk until just combined, without overmixing.
Transfer cake batter to prepared baking pan.
Bake at 340°F or 170°C for 35 minutes or until a toothpick inserted in the center comes out mostly dry.Let cake cool down 15 minutes in the pan, then take it out and let cool down completely on a wire rack.
Spread frosting on top, keep in the fridge if not eating it immediately.
Cut into squares, then you can add sprinkles on top before eating.
FROSTING
Soften butter at room temp for 15 minutes, then add it to a mixing bowl with vanilla extract and beat with a hand mixer for 30 seconds.Optionally, you can add grated lemon zest for some tang.
Add the cream cheese and beat for 30 more seconds.
Add powdered sugar, beat on low speed first, scrape down sides, and finish beating on medium-high speed until perfectly smooth. Don't overbeat it.Let it firm up in the fridge for 30 minutes, or in the freezer for 15 minutes, before applying it on the cake.