Goodness knows we love a good rainbow dessert recipe at Tablespoon, and these cute layered mini cakes are no exception! They look impressive, but they're easier to make than you'd think. The hardest part is coloring and layering the batter, and that's not even hard. (Don't you love it when the easy recipes are the most impressive looking?) We tested this recipe multiple times, and here are the tricks we picked up for guaranteeing rainbow cake success: • Batter amounts: it's definitely easiest to divide the batter into five equal batches for coloring, but we did find the bottom (purple) layer looked thicker than the others after baking. Basically, every time you pour in a new color, it kind of sinks to the bottom/center (gravity in action!) and pushes the batter that was already there up and out. So even though there's the same amount of each color batter, whatever one you put in first gets distributed up the sides of the jar more than the others. You may want to try tweaking the amounts of each color for a perfectly even rainbow, but we dig the tie-dye effect that naturally occurs when layering the colors. • Bake time: ovens vary, but we found we needed the full 40 minutes of bake time. You don't want the cakes to be over-done, but as long as they don't start to brown on top you should be okay. • Deflate-gate: as the cakes cool they sink in the jar just a little bit. Don't worry if this happens! It's just moisture escaping as things cool down, and it's totally okay.