We all know smoothies are a quick, simple meal or snack--but using these frozen smoothie cubes makes crafting the perfect green smoothie even easier! And if you're looking to add extra veggies to a soup, pesto, or dip, they're perfect for that too!

Keeping spinach in the refrigerator can be tough. It gets shoved to the back of the crisper drawer and turns slimy--until you need to for a smoothie and find it's all wilted and gross. Because of this problem (and my husband's recent obsession with this green smoothie), I created this solution and I wanted to share it with you!
Nutrient Notes about Spinach
Spinach is such an awesome leafy green because it's packed full of necessary nutrients, especially Vitamin A, Vitamin K, Vitamin C, Calcium, Folate, and non-heme iron.
Non-heme iron is the form of iron found in plants. Our bodies can absorb only about 3-20% of the iron from the spinach. In this recipe, we add lemon juice, a source of Vitamin C, to help boost the absorption of non-heme iron.
If you're looking for more ways to incorporate spinach into other meals, check out these recipes that are all dietitian-approved!
What substitutions can I make for spinach?
Any leafy greens like kale, swiss chard, or lettuce will work, but feel free to get creative! When choosing your greens, keep in mind the level of bitterness and how that will affect the final product. Rainbow swiss chard could make for a really beautiful smoothie, but I would suggest blending the beautiful red stems and dark green leaves separately. Because of the stark color difference, you may end up with a not-so-appetizing color.

The creative possibilities for these frozen spinach cubes are infinite--and that's what makes them great! The main idea here is to use this recipe to add more vegetables into your daily routine, and customize & create unique flavor combinations that make an incredible smoothie!
Recipe Tips & Tricks

As you're blending everything together in the food processor, you likely won't be able to completely liquefy the spinach. It should look like this:
What can I add to boost the flavor of my frozen smoothie cubes?
Ginger: The sweet, spiciness of ginger adds a kick to any smoothie--and it's been used throughout history to reduce nausea, which is great if you're making a hangover recovery smoothie.
Fresh mint: The natural oils in the mint leaves create a wonderfully aromatic experience, and can also help soothe nausea.
Coconut: As one of my personal favorites, coconut adds a more tropical flavor; it's also a great source of fiber and plant-based saturated fat, both of which will help keep you feeling full for longer. Choose unsweetened coconut & let the other fruit naturally sweeten your smoothie!
Citrus Zest: I love adding zest, particularly from grapefruits and lemons. It adds brightness and a slight bitterness that can help complement the sweeter fruits in your smoothie.
Cardamom: Adds that "chai" flavor that is so soothing & beloved.

Nutrient Boosts for your Frozen Smoothie Cubes
Avocado: Adding avocado to these frozen spinach cubes is a great option; you're adding extra fiber as well as heart-healthy fat, both of which help keep you feeling satisfied for longer.
Oats: Uncooked oats are an easy addition, and they add a bit of texture, as well as fiber and protein, which also help keep you feeling satiated.
Ground Flax Seeds & Chia Seeds: Like the oats, both of these seeds add texture and fiber, & are also sources of healthy fats.
Sweet potato: It may sound a little odd, but cooked sweet potatoes are a delicious addition to a smoothie (sweet potato + rainbow swiss chard stems would be a gorgeous combination!), especially when blended with mango. Sweet potatoes are a great source of fiber, as well as Vitamin A, which is important for immunity, vision, cell growth, and immunity.
Whether you make these frozen spinach smoothie cubes exactly like the recipe or come up with a new flavor combo, let me know in the comments. I can't wait to hear about the new flavor & nutrient combinations you create!
All my love & a little butter,
Olivia Sokolowska, MBA, RD

Frozen Smoothie Cubes
Adding extra veggies to your life has never been easier--these frozen smoothie cubes make whipping up a green smoothie quick & painless!
Ingredients
- 8 oz fresh spinach
- ½ cup water
- 3 tablespoon lemon juice
Instructions
1. Rinse the spinach and lay it out on a large cutting board or baking sheet.
2. Sift through the spinach and pull out any leaves that have gone bad.
3. Add the spinach, water, and lemon juice to a blender or food processor and blend until smooth, stopping periodically to scrape down the sides.
4. Pour the mixture into ice cube trays and freeze for 4 hours. Once the cubes are completely frozen, pop them out of the tray and transfer them to a freezer bag or airtight container.
*For a full serving of vegetables, add 5 cubes to the smoothie of your choice.
Notes
*The ice cube trays I use hold about 1.5 tablespoon of liquid per cube. This recipe makes ~20 cubes.
*At this size, 5 frozen spinach smoothie cubes = 1 serving of vegetables (the equivalent of 2 cups of leafy greens).
Nutrition Information
Yield
4Serving Size
5 cubesAmount Per Serving Calories 16Total Fat 0.3gSaturated Fat 0gTrans Fat 0gSodium 47mgCarbohydrates 2gFiber 1gSugar 0.5gProtein 2g
Please note that nutrition information is a computer-generated estimate and should not be interpreted as a registered dietitian's advice. Nutrition facts calculations vary based on brands, products, and serving sizes.
Mary Anne says
No I have not, but I do this with fresh spring dandelions, and garlic mustard greens, and freeze the cubes for winter soups. I will give your recipe a try, because I often wind up with tossing out unused slimy spinach leftovers.
Salted Butter Kitchen says
Freezing garlic mustard greens into cubes for soup in the winter sounds delicious, Mary Anne! Definitely give this one a try and let me know how it turns out.