Pumpkin Spice Latte Bath Bombs in a Cup – A Fall-Inspired DIY Treat for Your Tub

This cozy DIY bath bomb recipe looks just like your fave fall coffee—served in a paper cup with a whipped topping and straw! It fizzes, foams, and smells like pure pumpkin spice bliss.

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What you need

Dry Ingredients:

1 cup baking soda

½ cup citric acid

½ cup cornstarch

½ cup SLSA (Sodium Lauryl Sulfoacetate – for foam)

¼ cup Epsom salts

1 tsp pumpkin pie spice

1 tsp cinnamon (optional for scent boost)

Wet Ingredients:

2 tbsp sweet almond oil (or coconut oil)

½ tsp polysorbate 80 (prevents staining)

½ tsp vanilla extract or vanilla fragrance

10 drops pumpkin spice fragrance oil

Witch hazel in a spray bottle (to bind)

For “Whipped Topping” Frosting:

½ cup baking soda

¼ cup cream of tartar

1 tbsp SLSA

2 tbsp liquid castile soap

2 tbsp melted cocoa butter or shea butter

1 tsp vanilla fragrance

Mica powder (optional) for color – ivory, caramel, or cinnamon swirl

To Assemble:

4 small paper coffee cups (8 oz)

Paper straws

Piping bag or ziplock

Cinnamon for dusting

Instructions

Step-by-Step Instructions

1. Mix the Bath Bomb Base

In a large bowl, whisk together all dry ingredients. Make sure there are no lumps—especially in the citric acid or SLSA.

In a separate container, combine sweet almond oil, fragrance, vanilla, and polysorbate 80. Slowly drizzle into the dry mixture, whisking constantly.

Spritz with witch hazel a few times until the mixture feels like damp sand and holds its shape when squeezed.

2. Fill the Cups

Scoop the bath bomb mixture into each coffee cup, packing it in firmly. Leave about 1 inch of space at the top for your “foam.” Let them sit and harden while you prep the topping.

3. Make the Bubble Frosting

In a clean bowl, combine the baking soda, cream of tartar, and SLSA. In a microwave-safe bowl, melt the cocoa butter, then stir in the castile soap and fragrance.

Mix wet and dry together until fluffy. Add mica if you’d like to color it a creamy latte shade. Spoon into a piping bag and swirl it on top of each bath bomb cup like whipped cream.

Pop in a paper straw, tilted slightly for that coffee shop vibe.

Dust with a pinch of cinnamon or cosmetic-grade shimmer.

4. Dry & Store

Let your bath bomb lattes sit overnight in a cool, dry place to harden. Once dry, store in a sealed container or wrap individually for gifts.

To Use:

Run a warm bath and drop the whole cup in—yes, cup and all! The bath bomb will fizz and foam while the cup breaks down slowly (just remove any residue before draining). The whipped topping will bubble and release nourishing oils into your bath.

Tips & Variations

• Want more foam? Add a little extra SLSA to the frosting!

• For a fun gift set, pair with a pumpkin sugar scrub or a PSL lip balm.

• Try biodegradable or compostable cups if you’re feeling extra earth-friendly.

This bath bomb is fall in a cup, minus the calories and the caffeine jitters. It’s warm, spicy, cozy, and completely handmade. Whether you’re making them for your girlfriends, your Etsy shop, or just yourself (you deserve it), this Pumpkin Spice Latte Bath Bomb is an autumn must-have.