For the Strawberry Yellow Sheet Cake

• First, make the yellow sheet cake. Position a rack in the center of the oven and preheat the oven to 350°F. Generously spray an 9 x 13-inch pan with cooking spray and line the bottom with parchment paper. Spray the parchment, too.
• In a medium bowl, whisk together the flour, baking powder, and salt.
• In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and sugars. Beat on medium until light, fluffy, and doubled in volume,3 to 4 minutes, using a rubber spatula to scrape down the bottom and sides of the bowl as necessary. Reduce the mixer to low and add the eggs one at a time, adding the next egg only after the previous one has been fully incorporated, scraping down the bottom and sides of the bowl after each addition. With the mixer on low, slowly pour in the oil, followed by the buttermilk and vanilla, and beat until the mixture is smooth, 3 to 4 minutes. Gradually add the dry ingredients and beat until just combined. Scrape down the bottom and sides of the bowl once more, and beat on low for an additional 30 seconds.
• Pour the batter into the prepared pan and use an offset spatula to smooth its top if necessary.
• Bake the cake. Bake for 40 to 45 minutes. When done, the top of the cake should bounce back when gently pressed and a skewer inserted into the center of the cake should come out with a few crumbs attached. Cool completely in the pans on a wire rack before frosting.
• Once the cake is cool, make the strawberry buttercream frosting. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, food coloring, and vanilla on medium-low until soft and creamy, 2 to 3 minutes. Scrape down the bottom and sides of the bowl with a rubber spatula. With the mixer on low, gradually add the confectioners' sugar, freeze-dried strawberries, and salt and beat until combined. Scrape down the bottom and sides of the bowl once more, then beat on medium-high until the frosting is creamy and smooth, 2 to 3 minutes.
• Assemble the strawberry yellow sheet cake. Use an offset spatula to cover the top of the cake with the frosting completely. Garnish with sprinkles.
• Serve and store. Serve at room temperature. The cake will keep in an airtight container for 1 day. After that, transfer to the refrigerator and refrigerate for up to 2 more days.