Preheat oven to 300 degrees F. Stack two matching, heavyweight, light to medium colored cookie sheets one inside the other (stacking two cookie sheets together keeps the bottoms of the cookies from getting too brown). Line with parchment paper or a silicone baking mat.

Set out three medium mixing bowls. Mark or label the bowls so you know which one will hold each color dough (plain, strawberry, and chocolate).

Measure out 100g of almond flour (a heaping cup) into each bowl.

Remove 2 tablespoons (about 10g) worth from the "strawberry" bowl and put it in the "plain" bowl. So you'll have 110g in the plain bowl, 100g in the chocolate bowl, and 90g in the strawberry bowl.

Measure out 90g (a scant half cup) of sugar into each bowl; add a pinch of salt to each bowl as well.

Finely grind freeze dried strawberries in a food processor or spice grinder until finely ground powder. If you want you can put a little of the sugar from the strawberry bowl into the grinder to weight down the fruit and grind it more evenly. Pour powder into strawberry bowl and whisk until evenly incorporated.

Add cocoa powder to the chocolate bowl and whisk until evenly incorporated.

Whisk the contents of the plain bowl until the sugar and almond flour are also evenly incorporated.

In a mixing bowl or the bowl of a stand mixer fitted with the whisk attachment, whisk egg whites and lemon juice until they hold soft peaks. Add almond extract and mix for just a second or two to incorporate.

Here's where your scale will really come in handy! Place one bowl of dry ingredients on the scale and tare it to 0. Spoon in 30 grams of beaten egg whites and stir until mixture forms a soft, sticky dough, kneading with your hands if necessary. No need to be gentle here, we're not making macarons. ;)

Repeat with the chocolate bowl, taring the scale to 0 and adding 30 grams of egg whites, then stirring until it comes together.

Do the same for the strawberry bowl, adding 30 grams of egg whites and, if desired, a drop or two of pink food coloring to enhance the color. Stir until color is evenly distributed throughout the dough.

Lightly dust your hands with powdered sugar. Use a small cookie scoop to portion out three 1-inch balls, one of each flavor dough. Roll the three balls together into a log shape, rolling so that the three colors are evenly stretched along the length of the log. Twist the ends in opposite directions once or twice to further marble the dough. Dip a small knife in powdered sugar and cut log into 3 even pieces, then roll each piece into a smooth ball. Arrange on prepared baking sheet, leaving 1 inch of space between cookies. Repeat with remaining dough (you'll likely have enough dough for two full cookie sheets, so shape half of it, then shape the remaining half while the first pan is baking).

Bake for 25 to 30 minutes until tops are cracked and bottoms are just barely golden. Note if you are NOT using doubled cookie sheets the bottoms of your cookies will brown much quicker, so they will probably be done sooner—start checking them around 20 minutes or so. Also, if you opted not to add food coloring, your pink dough will start to brown the longer they bake.

Remove from oven; let cool a few minutes, then transfer to wire racks to cool completely. Let the pans cool before you start placing the second half of the cookies.

Cookies will keep at room temperature in an airtight bag or container for up to 5 days or frozen for up to 1 month.