While the origin of birthday cake is more complicated than high school geometry, I'm still a sucker for a good ol' slice of tradition. My mom has made some epic birthday cakes over the years. When I was four, I had a train with five passenger cars made out of chocolate sponge. When I was eight, I had a Barbie with a skirt made out of angel food cake and marshmallows. Needless to say, I'm picky when it comes to birthday cake ideas, but these 21 cakes still managed to blow my mind.

Galaxy cake. Piñata cake. Rainbow cake. These are the things that childhood dreams are made of.

1. Galaxy Cake

cake, chocolate, cream
Paige Marie Rodgers

Take your birthday cake game to infinity and beyond with this epic galaxy cake. If you think the outside is cool, just wait until you cut into the cake; there's a whole solar system hidden beneath the icing.

2. DIY Momofuku Milk Bar Cake

cream, ice, ice cream, sprinkles, cake
Grace Phillips

Save yourself $42 by making this Momofuku Milk Bar Birthday Cake at home. It has the same buttercream frosting and cake crumbles as the bakery version, but it will cost you a quarter of the price to make.

3. Marbled Zebra Cake

chocolate, cake, cream, pie, sweet, pastry, goody, brownie, candy, chocolate cake, mousse
Emma Delaney

This marbled zebra cake is like a good book: the outside might look unimpressive, but it has hidden depths. The best part? This recipe only calls for two boxes of cake mix and some icing. It's easy to throw together as a last-minute, sorry-I-forgot-your-birthday cake.

4. Funfetti Cake

You know how some people tear up when they see a gorgeous sunset? I'm tearing up just looking at this funfetti cake. Who knew that birthday cake ideas would make me so emotional?

5. Watermelon Cake

sweet, chocolate
Samantha Ho

We all have a health nut in our lives, and this watermelon cake is the perfect alternative to the usual sugary cake. The only ingredients are Cool Whip, almonds, and fruit, so your loved one can enjoy her or his birthday cake without sacrificing those gym goals.

6. Piñata Surprise Cake

candy, sprinkles, cake, chocolate, sweet, goody, cream, sweetmeat
Paige Marie Rodgers

Forget batting a cardboard pony around with a bat until some prizes fall out; cutting into this piñata surprise cake is way more satisfying. Ngl, this might be the most Insta-worthy dessert that I have ever seen.

7. Cookie Birthday Cake

cake, birthday cake, chocolate
Sydney Youmans

This epic cookie birthday cake layers three types of cookies: M&M, Funfetti, and triple chocolate. And just in case that wasn't enough for you, it's sandwiched together with cookie dough frosting. Yes, please.

8. Kit Kat and M&M Cake

Honestly, I wish this kit kat cake was bigger because I would give my right hand to swim in a chocolate pool filled with m&ms. It's like the ball pits that you sometimes see at birthday parties, but way tastier.

9. Bunny Cake

cake, cookie, chocolate
Ansley Levine

Don't worry: this bunny cake isn't actually made out of rabbit. This cake might be intended for Easter, but there's no reason that bunny-lovers shouldn't enjoy it on their birthdays. What are you waiting for? Hop to it.

10. Rainbow Sherbet Cake

cake, cream, meringue
Caitlyn Heter

My sister is the type of gal that treats ice cream cake as its own food group, and after seeing this rainbow sherbet cake, I'm starting to understand why. Did I mention that it only has 5-ingredients? Yes. Dreams do come true.

11. Mango Rose Cake

cake, cream, sweet
Rehmat Babbar

This mango rose cake tastes as impressive as it looks. Plus, it's dairy-free, so it's the perfect birthday cake for any lactose-intolerant friends.

12. Pumpkin Mini Cakes

Talk about trompe l'oeil. One moment, you think you're biting into a squash, and the next thing you know, you have a mouthful of cinnamon-y cake. These pumpkin mini cakes are perfect for any birthdays in the fall.

13. Peanut Butter and Oreo-Stuffed Cupcakes

chocolate, cake, pastry, sweet, cookie, brownie, cream, candy
Rebecca O'Neill

Okay, so technically these are cupcakes, but that just means that your cake is already divided into ready-to-eat portions. Also, it would have been a crime not to include these peanut butter and Oreo stuffed cupcakes. I'm drooling just looking at them.

14. Rainbow Roll Cake

cake, candy, cream, sweet, pastry, chocolate
Paige Marie Rodgers

Is this rainbow roll cake taking the rainbow bagel craze a bit too far? Probably. Do I intend to make it anyways? Hell, yeah I do. With less than 10 ingredients, this cake is almost too good to be true.

15. Unicorn Cake

I'm not the biggest supporter of the unicorn trend, but even I have to admit that this unicorn cake is pretty darn cute. If you think the decorations are impressive, just wait until you cut this thing open.

16. Chocolate Peppermint Cheesecake

chocolate, cake, sweet, cream, pastry, candy, brownie
Paige Marie Rodgers

Honestly, just looking at this chocolate cheesecake is making me dream of Christmas. And it's only July. If your birthday is in the winter, then I'm supremely jealous because this chocolate cheesecake would make a splendid birthday cake.

17. Vegan Chocolate Biscoff Ice Cream Cake

cereal, sweet, wheat, chocolate, corn
Shivangi Surana

Honestly, the fact that this biscoff ice cream cake is made out of bananas absolutely blows my mind. Does that basically make it a fruit salad? Probably not. But I'll still use it as a justification for eating half the cake.

18. Mermaid Tail Cupcakes

I watched The Little Mermaid approximately 10,000 times growing up, so these mermaid cupcakes are a throwback to my childhood. I'm pretty sure I would cry with happiness if someone made these for me. Hint, hint, friends.

19. No-Bake Oreo Cheesecake

chocolate, cake, cheesecake, pie, cream, sweet
Kierri Price

Whoever thought of turning an Oreo cheesecake into a massive Oreo is a genius and deserves a prize. This dessert is filled with mascarpone, white chocolate, and Oreos (duh). And you don't even need an oven to make it.

20. Starry Night Cupcakes

cupcake, cake, buttercream, cream
Sam Jesner

If your friend is a total art nerd, then these starry night cupcakes will paint a smile on her face (too far?). Van Gogh would be chuffed by this masterpiece. 

21. Birthday Cake Shots

candy, chocolate, cream, sprinkles, sweet, milk, goody, cake
Courtney Lewis

Is it a coincidence that these birthday cake shots are number 21? No, my friends. That is fate (and good planning). Celebrate your first birthday as a bona fide adult with these cake-inspired shots filled with cake vodka, white chocolate liqueur, and rainbow sprinkles.

These birthday cake ideas are the kind of thing that you might expect to find on Insta or Pinterest. If you want to get fancy for your next birthday or a friend's big day, whip one of these recipes up. Your only problem will be convincing the guests to stop taking photos of the cake long enough to eat it.