Homemade Blackberry Marshmallows with Agar Agar
Elegant homemade marshmallows featuring vibrant blackberry puree and agar agar instead of gelatin, creating a naturally fruity and beautifully colored confection. The blackberries are simmered into a concentrated puree that gets whipped with egg whites, then combined with a hot agar syrup to create pillowy soft marshmallows with intense berry flavor. Piped into decorative rose shapes, these marshmallows make an impressive dessert or gift. The agar agar provides a firmer set than traditional gelatin versions while keeping the recipe accessible to vegetarians.
Ingredients
Instructions
- 1
Bring blackberries, 1/2 cup sugar and lemon juice to a simmer in a medium saucepan
- 2
Mash berries and simmer uncovered 10 minutes then strain through a fine sieve, pressing solids with a spatula
- 3
Scrape back of sieve to ensure you have 1/2 cup puree and chill over an ice bath until cooled
- 4
Combine chilled puree with egg white in stand mixer bowl fitted with whisk attachment
- 5
Beat on high speed 8-10 minutes until mixture is thick and stiff peaks form
- 6
In medium saucepan, stir together water, agar agar and 1 cup sugar
- 7
Place over medium heat, bring to a boil then reduce to low boil and cook 5 minutes, whisking constantly until syrup thickens
- 8
Remove syrup from heat
- 9
With mixer on lowest speed, immediately pour hot syrup in thin stream into whipped blackberry mixture, avoiding whisk and bowl
- 10
Scrape down bowl and beat another 2-3 minutes on high speed until stiff peaks form
- 11
Transfer mixture to piping bag fitted with Wilton 1M large open star tip
- 12
Pipe roses onto parchment-lined baking sheet, keeping roses even in size
- 13
Let stand uncovered in draft-free, low humidity area at room temperature for 6-12 hours or overnight until glossy film forms
- 14
Match two halves together then roll sandwiched marshmallows in powdered sugar
Tips
Chill the blackberry puree completely before whipping to ensure proper texture and volume when beaten with egg whites.
Pour the hot agar syrup immediately after removing from heat in a thin stream to prevent it from setting before incorporation.
Store finished marshmallows in an airtight container at room temperature for up to one week, dusting with additional powdered sugar if they become sticky.
Good to Know
Store in airtight container at room temperature up to 1 week
Can be made 1-2 days ahead, store covered at room temperature
Serve at room temperature as individual treats or paired with hot chocolate
Common Mistakes
Pour syrup immediately after removing from heat to avoid premature setting
Keep mixer on lowest speed when adding hot syrup to prevent splattering
Ensure completely draft-free environment during setting to prevent uneven drying
Substitutions
FAQ
Can I use frozen blackberries instead of fresh?
Yes, frozen blackberries work well. Thaw completely and drain excess liquid before cooking to maintain proper puree consistency and concentration.
What if my agar syrup starts to set before I add it?
Reheat gently while whisking until liquid again, then immediately pour into the mixer. Work quickly as agar sets faster than gelatin.
How long will these marshmallows keep?
Store in an airtight container at room temperature for up to one week. Dust with additional powdered sugar if they become sticky.