Sugar-Free Black Widow Cocktail

This spooky low-carb cocktail is perfect for your Halloween celebration! The homemade blackberry-lime syrup gives it a deep, fruity flavor that pairs perfectly with vodka. To keep it keto-friendly, I swapped the usual simple syrup for allulose, which adds sweetness without the carbs. Whether you're hosting a Halloween party or just want a festive drink, this cocktail is easy to make and has a beautiful dark hue that fits right in with the spooky theme.

Key Ingredients & Swaps

Here are the key ingredients you’ll need for this cocktail and some alternative options to try:

• Blackberries: The base of this cocktail's syrup. You can use fresh or frozen blackberries. If you’re out of blackberries, raspberries can be a good substitute, but keep in mind that the flavor will be slightly different.
• Lime Juice: It adds a fresh, tangy kick that balances the sweetness. Lemon juice works just as well if that's what you have on hand.
• Powdered Sweetener: I've tried both allulose and erythritol for the sugar-free syrup. Both worked well although allulose is better as it creates a better syrupy consistency and has no cooling aftertaste. For a sweeter cocktail you could even add a few drops of stevia.
• Vodka: A classic choice for this drink, but you can swap it with white rum if you prefer a different base.
• Sparkling Water (Optional): Adds a light, fizzy finish to the cocktail. You can skip this if you want a stronger drink.
• Garnishes: You can decorate with acai powder or any freeze-dried berry powder mixed with a bit of granulated low-carb sweetener for a spooky, dusted rim. Fresh blackberries and mint leaves also make great garnishes.

Where to Get Allulose

There are a few options available on Amazon. The brand I use and like is RxSugar. If you live in the US you can get RxSugar 20% off by using this link (affiliate link) or by using the code KETODIET20 at checkout. For those outside the US, it can be a bit more challenging to find, but you can order it in bulk and have it shipped to the UK.

Tips for Making the Perfect Black Widow Cocktail

For a smooth and impressive cocktail, keep these tips in mind:

• Strain Well for a Smooth Syrup: When mashing and straining the blackberries, make sure to use a fine mesh sieve and press with a spoon to get as much juice as possible while leaving behind seeds and pulp. This will give you a smoother syrup.
• Avoid Over-sweetening: If you’re using pre-made simple syrups or stevia drops, start with a smaller amount and taste as you go. You can always add more sweetener, but it’s hard to fix an overly sweet drink.
• Serve Cold: Make sure the syrup and vodka are well-chilled before mixing the cocktail. It enhances the taste and keeps the drink refreshing.
• Get Creative with Decorations: Dip the rims of your glasses in water, then in a mix of acai powder (or any berry powder) and granulated low-carb sweetener. It creates a spooky, dark rim that's perfect for Halloween vibes.
• Prep the Syrup in Advance: You can make the blackberry syrup up to a week ahead and store it in the fridge. This way, all you need to do is assemble the cocktail when it's time to serve.

Storage Tips

Keep the homemade blackberry syrup in a sealed bottle or jar in the refrigerator. It will stay fresh for up to a week. If the syrup thickens in the fridge, just let it sit at room temperature for a few minutes before using. Shake before use.

Similar Recipes You'll Love

Looking for more cocktails and Halloween-inspired snacks? Check out some of these recipes:

• Spicy Low-Carb Margarita
• Halloween Sausage Mummies
• Spooky Eyeball Deviled Eggs
• Spooky Chocolate Mug Cake
• Halloween Cheesecake Brownies
• Black Heart Cupcakes

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Step-by-step

1. Place the blackberries in a saucepan. Add the lime juice and water. Bring to a boil over a medium heat. Boil for 3-5 minutes.

   

2. Once softened, mash the blackberries using a fork. Pour through a fine mesh sieve and using a spoon, press the blackberries through so that only the skins and seeds remain in the sieve.

   

3. Pour into a jar. The juice should be quite thick, the consistency of syrup.
   Note: This recipe makes about 2 ¹/₄ cups (530 ml/ 18 fl oz) of blackberry syrup. This will be enough for 6 cocktails.

   

4. Add the powdered sweetener and mix until combined. Let it cool and refrigerate until ready. The syrup can be stored in the fridge in a sealed bottle or jar for up to a week.

   

5. To serve, optionally decorate your cocktail glasses by dipping the rims in water and then in a mixture of acai powder (or any berry powder). Fill each glass with ice and pour in the vodka.

   

6. Add the sweetened blackberry juice.

   

7. Decorate with more fresh blackberries or mint leaves and serve.

   

Recipe

Sugar-Free Black Widow Cocktail

★★★★☆4.2 (87 ratings)

Low-carb cocktail with homemade blackberry-lime syrup and vodka. This is the perfect sugar-free and ...

Hands on

10m

Overall

30m

Servings

1

4.7 g

Net carbs

1 g

Protein

0.4 g

Fat

165

kcal

1 serving2 servings3 servings4 servings5 servings6 servings7 servings8 servings9 servings10 servings11 servings12 servings

US + metricMetricUS

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Ingredients makes 1 cocktail

• Homemade Blackberry Syrup:
• 450 g fresh or frozen blackberries (1 lb)
• ¹/₄ cup lime or lemon juice (1-2 pieces)
• 1 cup water (240 ml/ 8 fl oz)
• ¹/₂ cup granulated Allulose or Erythritol (100 g/ 3.5 oz)
• Each Cocktail:
• 90 ml homemade blackberry syrup (3 fl oz)
• ¹/₄ cup vodka (60 ml/ 2 fl oz)
• ice, to taste
• Optional: sparkling water (soda water) to top up
• Optional: acai powder or freeze-dried berry powder mixed with granulated Erythritol, and fresh blackberries for decoration

Instructions

1. Place the blackberries in a saucepan. Add the lime juice and water. Bring to a boil over a medium heat. Boil for 3-5 minutes.

2. Once softened, mash the blackberries using a fork. Pour through a fine mesh sieve and using a spoon, press the blackberries through so that only the skins and seeds remain in the sieve.

3. Pour into a jar. The juice should be quite thick, the consistency of syrup.
   Note: This recipe makes about 2 ¹/₄ cups (530 ml/ 18 fl oz) of blackberry syrup. This will be enough for 6 cocktails.

4. Add the powdered sweetener and mix until combined. Let it cool and refrigerate until ready. The syrup can be stored in the fridge in a sealed bottle or jar for up to a week.

5. To serve, optionally decorate your cocktail glasses by dipping the rims in water and then in a mixture of acai powder (or any berry powder). Fill each glass with ice and pour in the vodka.

6. Add the sweetened blackberry juice.

7. Decorate with more fresh blackberries or mint leaves and serve.

Nutrition per cocktail

Carbs 72%Protein 16%Fat 12% of calories

Net carbs

4.7 g

Total carbs

8.6 g

Fiber

3.9 g

Sugars

3.7 g

Protein

1 g

Fat

0.4 g

Saturated fat

0 g

Calories

165 kcal

Sodium

8 mg · 0.33% RDA

Magnesium

17 mg · 4.19% RDA

Potassium

129 mg · 6.47% EMR

Nutrition by ingredient

Per cocktail	Net carbs	Protein	Fat	kcal
Homemade Blackberry Syrup	4.7 g	1 g	0.4 g	37
Vodka, distilled alcoholic beverage (~40% vol)	0 g	0 g	0 g	128
Ice cubes	0 g	0 g	0 g	0
Total	4.7 g	1 g	0.4 g	165

Serving size cocktail

• Gluten free
• Dairy free
• Egg free
• Nut free
• Nightshade free
• Pork free
• Avocado free
• Coconut free
• Fish free
• Shellfish free
• Beef free
• Pescatarian
• Vegetarian
• Vegan