We’re right smack dab in the middle of blueberry season. And though they look blue when you pick them, a few minutes of simmering turns those blueberries unmistakeably purple. I love using fragrant lavender as a seasoning (also in season now), but enough lavender to color this dish would have made it inedible. Luckily for me, blueberries and lavender make an amazing flavor combination.
Semifreddos (transl: semi-frozen) are a wonderful dessert, and an especially wonderful way to make a frozen treat without an ice cream machine. Cream (and sometimes egg whites) are whipped, folded into a sweet, flavored base and then frozen. For this semifreddo, I made a lavender syrup, gently poached the blueberries, then folded some of the thickened syrup into whipped cream. You can shape a semifreddo with just about anything you want– muffin tins, a loaf pan, paper coffee cups. Just line the mold with plastic wrap, fill with your beautiful whipped filling and a few hours later you’ll have an elegant frozen treat. Semifreddos are at their best when they are served with a contrasting warm element. For this dish, I’ve kept some of the blueberries warm to contrast the cold of the semifreddo. And I added a walnut streusel for just a little crunch and a delicious nutty flavor.
2 ½ t. dried or fresh lavender flowers
1 t. loose leaf earl grey tea or one bag of earl grey tea
⅔ – ¾ c. sugar (adjust quantity to taste)
1 c. water
1 pt. blueberries
½ t. corn starch
1 1/2-2 c. whipping cream
⅓ c. walnuts
¼ c. brown sugar
¼ c. butter
¼ c. flour
Make Lavender Syrup
Place lavender, tea, sugar and water together in a saucepan and bring to a boil. Remove from heat and let infuse for 10 minutes. Strain out the lavender and tea.
Toast walnuts in a 350°F oven for 10 minutes, until lightly browned. Reduce oven heat to 300°F. Set aside to cool. Cut butter, brown sugar, flour and salt together until the mixture resembles a coarse meal. Chop the walnuts and add to the streusel. Spread the streusel mix out onto a parchment-lined baking sheet and bake for 10-15 minutes, until the streusel is lightly browned and crisp. Stir and rotate the sheet once during baking.
Bring the strained syrup to a boil and add in the blueberries. Turn the heat down to low and simmer for 2-3 minutes. Turn off the heat and leave the blueberries to poach for 10-15 minutes, until tender. Strain syrup, in all likelihood a few blueberries will have broken down in cooking and left the syrup purple. If not crush a few blueberries into the syrup and strain out the skins. (You want a little fruit in the syrup) Place the syrup over high heat and boil for 5 minutes. The syrup should reduce and slightly thicken. Mix ½ t. corn starch with 1 t. cold water. Add the corn starch slurry to the boiling syrup and cook for one minute, stirring constantly while the syrup boils. Measure out ⅓ c. of the blueberry syrup (this should be most of it). Pour the ⅓ c. syrup into a bowl, cover and refrigerate until cold. If you are making the semifreddo immediately place the bowl of syrup in an ice water bath to cool it down more quickly. Pour the rest of the syrup in with the blueberries.
Once the syrup has chilled, you can mix and mold the semifreddo. Line whatever your semifreddo mold with plastic wrap. Whip 2 c. cream to a soft peak. Do not overwhip! Once the cream starts to thicken the texture changes very rapidly. In a large bowl, gently a scoop of the whipped cream into the chilled blueberry syrup. Continue folding in more whipped cream until the mixture is a light purple color and tastes lightly sweet. (Adding more cream will make the semifreddo milder and firmer. Less cream and it will be stronger, sweeter and softer.) I added all two cups, and the texture of my semifreddo was pleasantly firm. (Though I followed up in the comments with a few notes on texture)
For a more textured semifreddo, fold in a few of the poached blueberries and some streusel topping. Delicately scoop semifreddo into molds and freeze for a few hours, until firm. Well covered, the semifreddo will keep in the freezer for several weeks.
Take semifreddo out of the freezer 10-20 minutes before you want to serve it, removing plastic wrap. Warm blueberries. Serve semifreddo with blueberries and streusel topping.