Preheat your oven to 350°F. Line a 9x13-inch baking pan with parchment paper, allowing it to hang slightly over the sides for easy removal later.

In a large mixing bowl, whisk together the flour, baking powder, baking soda, salt, and sugar.

Add the eggs, canola oil, buttermilk, and vanilla extract to the dry mixture. Whisk until the batter is very smooth and no dry spots remain.

Carefully pour the boiling water into the batter and whisk until thoroughly combined. (Don't worry—this will make the batter very thin. That’s precisely what you want!)

Use a spatula to gently fold in the rainbow sprinkles. Try not to overmix so the colors don’t bleed too much.

Pour the batter into the prepared baking pan. Bake in the center of the oven for 30 minutes, or until the cake is golden brown, pulling away slightly from the sides, and springs back when gently pressed.

Let the cake cool in the pan for 1 hour before turning it out on a wire rack and frosting.

In a large bowl, beat the softened butter and cream cheese together on low speed until smooth and fully combined.

Add the powdered sugar and strawberry preserve. Beat again until the frosting is smooth, creamy, and fluffy. (Optional: If you'd like a brighter pink frosting, add a drop of pink food coloring at this point.)

Once the cake is completely cooled, spoon the frosting over the top. Use an offset spatula to spread it evenly all over the surface.

Generously sprinkle the top of the frosted cake with rainbow sprinkles for that perfect Funfetti look.

Cut into squares and enjoy!