week 18. blueberry macs x blueberry buttercream + blueberry jam + crumble

using my base recipe, I subbed out cocoa powder for the equivalent amount of almond powder and finely ground freeze-dried blueberries.

I had made blueberry shells before using the full 37g of blueberry powder that I usually use, but I ground it up in advance this time, and by the time we
(my cousin Sydney helped me make this batch!) went to sift it, the powder had sort of re-glued itself together and was unusable. we were able to get about 10g of blueberry powder through the sifter and made up for the rest with almond flour. in the end, there was so much blueberry flavor coming through from the buttercream and jam, that it wasn't necessary to have used any more! somehow things always work out.

I would suggest making your crumble in advance and let it cool before you even start making the macs. that way you can use the crumble as decoration to top the macs (instead of crushed up blueberry kashi cereal like I did due to poor planning - ha!).

I always struggle to rank my macs because I think they're all really good. I knew last week's (creamsicle) were my least favorite, but I am usually unable to pick which is best. immediately after tasting this week's, I knew this was it–hands down my favorite that I've made so far.

ingredients | shells

mixture a:                  
freeze-dried blueberries
-finely ground                                            10g

almond flour                                                 27g
almond TPT*                                                300g
powdered sugar                                        38g

egg whites                                                      73g     

mixture b:
egg whites                                                      73g
salt                                                                       0.5g
water                                                                  50g
sugar                                                                  188g
light corn syrup                                          10g
light and dark blue
gel food coloring                                       5ish drops

* TPT means equal parts powdered sugar and another ingredient, in this case it’s almond flour, and you will use 150g of each to equal the 300g.

method | shells

bring all ingredients to room temperature.

use a blender (vitamix does a great job) to grind the freeze-dried blueberries until it becomes a fine powder. (do this immediately before measuring and sifting into mixture or it may glue itself together as mentioned in my notes above).

from “mixture a,” sift together the blueberry powder, almond powder, almond TPT, and powdered sugar into a large bowl and set aside. (it’s important to sift to make sure everything is very fine).

from “mixture b” whisk the egg whites and salt in a standing mixer with the whisk attachment set to 4 and leave it there while you make a syrup.

make a syrup from “mixture b.” first add the water, then the sugar, then the corn syrup into a small saucepan. pour the sugar in very slowly so that it all gets incorporated into the water, being very careful not to get any on the sides of the saucepan or your syrup can crystallize. do not stir!! stirring can also cause crystallization. just let it do its thing.

heat this syrup on medium until it boils and reaches 248°F. really, don’t stir it!

tip: you can take the chill off the eggs if you hold the bowl over the heating saucepan for a few seconds while swirling it around or whisking it (I like to whisk).

turn up the standing mixer to 8 to create soft peaks while the syrup is still heating up to the right temperature.

to create the meringue, slowly pour the hot syrup along the side of the bowl into the mixing egg whites and let it mix until it’s stiff, but still shiny.

take the egg whites from “mixture a,” plus a spatula full of the meringue and mix it into the sifted blueberry, almond, powdered sugar mixture that you made earlier. fold this together with a spatula until you form a thick paste.

drop in about 5 drops of your gel food coloring to amp up the color. (the last time I made blueberry shells, I left the color up to the freeze dried blueberry powder and they turned out pastel purple. I wanted to do it a little differently this time). then continue to fold the paste until the color is completely incorporated.

fold the rest of the meringue into that paste until it becomes glossy and slightly runny. (you’ll know when it’s done when the batter slowly falls off your spatula like a thick ribbon and settles into itself in the bowl after a few seconds. you don’t want it to be any runnier than that because you don’t want the mixture to spread once it’s piped).

pipe quarter sized bulbs onto parchment paper or a silicone baking mat on a sheet pan (I prefer silicone mats).

tip: if a little nub from where you released the piping bag doesn’t settle into itself, you can use a small paintbrush to tap it down.

tap the bottom of the pan a couple times to prevent any air bubbles while baking. (i actually tap it like 30 times because it's fun and it really does get the air bubbles out)

top your macs with small bits of the cooled crumble that you made earlier.

let your macs sit out for at least 10 minutes before going in the oven. this recipe uses the italian method, and I've read that you really don't have to do this unless you're using the french method. but ever since my successful, crack-less shells from week 10, I will continue to incorporate this step.

bake on your oven’s convection setting at 280° for 15 minutes. for the first 5 minutes with the oven door closed, and the remaining 10 minutes with a wooden spoon propping the oven door open a bit.

let cool completely before filling.

ingredients | blueberry buttercream + blueberry jam

1% milk                                                                1/4 cup
heavy cream                                                 1/4 cup
flour                                                                     3 tbsp

unsalted butter                                          1/2 cup
vanilla extract                                              1 tsp
granulated sugar                                       1/2 cup
blueberry jam                                              3 heaping tbsp, plus more
                                                                                for filling centers

method | blueberry buttercream + blueberry jam

bring butter to room temperature.

using a small sauce pan, heat the milk, cream, and flour on medium, whisking continuously until it becomes a pretty thick, paste-like consistency.

throw that goopy mound of paste into the fridge on a new plate or bowl and wait for it to completely cool.

use a hand mixer or whisk attachment on a standing mixer, set on medium-high, to cream the butter and sugar for a couple minutes until light and creamy.

add in the cooled milk paste/mixture and vanilla and beat on medium-high to combine for a couple minutes. scrape down the sides, and then continue to beat about 5 or so minutes until it's super fluffy and all of the sugar granules have dissolved.

add in the jam and continue to beat until fully incorporated.

pipe buttercream in a circle on half of the shells, leaving the center open to fill with a blob of jam.

fill centers with blob of blueberry jam. I found you don't need to overdo it. a small blob goes a long way with these.

stuff bits of your crumble along the outer edge of the buttercream and then sandwich your shells together.

refrigerate these guys when you're done. they actually taste better after a day of refrigeration than they do right after baking.

tip: the sizes of all of your shells will tend to be slightly different, so make sure you buddy up your shells to similarly sized partners so that the entire cookie is a consistent size.

ingredients | crumble

flour                                                                     1/2 cup
brown sugar                                                  1/4 cup
granulated sugar                                       1/4 cup

unsalted butter                                          3 tbsp

method | crumble

combine flour and sugars in a bowl.

cut butter into square cubes and cut into sugar/flour mixture using a pastry cutter until the butter is combined and resembles breadcrumbs.

spread out on a parchment paper covered baking sheet and toast in the oven on the middle rack on high broil for a couple minutes at a time. each time you check on it, stir around with a spatula to let all of the crumble toast evenly. repeat this until most of it is golden brown. you don't want to let it burn.

let cool before using.