Prep: Prepare the flax egg by combining the ground flax and water in a small bowl, then set aside for at least 5 minutes to thicken. Use a food processor knife to chop half of the freeze-dried strawberries into small pieces; set aside. Place the remaining strawberries in a blender or food processor (make sure it is completely dry!) and blend or pulse for 30 to 45 seconds until a fine powder forms; set aside. Note: do not open the blender/processor right away – it will be very dusty! I recommend keeping it sealed until adding the dry ingredients in step 3 after some of the powder settles.: When the flax mixture begins to thicken, you will notice it go from watery to slightly gel like, with a faint nutty scent that tells you it is ready. This transformation matters because it gives the dough binding power, preventing crumbly cookies. Avoid the mistake of rushing this step, as a thin flax mix will not hold the dough properly and can lead to flattening during baking. Also, when you pulse the freeze dried strawberries you will hear a high pitched chopping sound, and the processor will smell intensely fruity, which is normal. The fine powder will billow when you open the lid, so wait a moment for dust to settle, or open the lid slowly to avoid a pink cloud over your counter.
Cream the Sugar: Add the vegan butter to a large mixing bowl, then add in 1/3 cup of cane sugar and brown sugar. Use a handheld mixer to cream the butter and sugar together over a medium speed until light and fluffy, about 3 minutes. Add the thickened flax egg and vanilla to the bowl and beat again until the flax is fully incorporated into the butter mixture.: As you beat the softened butter with the 1/3 cup cane sugar and light brown sugar, listen for the mixer changing tone from heavy to lighter, and watch the mixture turn paler and fluffier after about three minutes. This aeration traps tiny air pockets that create a tender lift in the cookie, so don’t skimp on creaming. A common error is using butter that is too cold, which prevents proper aeration and yields denser cookies. Once you add the thickened flax and vanilla, the mixture should smooth and shiny, smelling warmly of vanilla with a subtle buttery note.
Dry Ingredients: Add the flour, strawberry "powder", baking powder, and salt to the bowl. Beat on the lowest setting of your mixer and mix until just combined, using a spatula to scrape the sides of the bowl if necessary. Add the chopped freeze-dried strawberries to the bowl and fold them into the batter. Cover the cookie dough with plastic wrap and place in the fridge to cool for 60 minutes, or up to overnight.: When you add the flour, powdered strawberry, baking powder, and salt and mix on low, you will see the dough transform from sticky to manageable, with streaks of pink from the powder. Mixing slowly prevents overworking the gluten, which keeps the cookies tender rather than chewy. If you overmix here you risk a tougher crumb, so stop as soon as the streaks disappear and fold in the chopped strawberries gently, noticing little bursts of red against the pale dough. Using a spatula to scrape the bowl ensures everything is evenly incorporated without excessive beating.
Form the Cookies: Preheat the oven to 350 F while the cookie dough is chilling and line a baking sheet with parchment paper. Place the remaining 2 tablespoons of sugar in a small bowl. Divide the cookie dough into 12 even balls (mine were just under 2 tablespoons each), using your hands to roll into small spheres. Roll each cookie dough ball in the cane sugar until fully coated, then place on the lined baking sheet about 2" apart. Use your hands to flatten each cookie dough ball slightly – they will spread some in the oven, but not a lot.: As the dough chills, it firms and the flavors meld, and it will be noticeably easier to handle. Preheating the oven to 350 F warms the baking environment for consistent rise, and lining a baking sheet with parchment prevents sticking and encourages even browning underneath. When you roll each ball and coat it with the remaining 2 tablespoons sugar, you will feel a slight granulated crunch on the surface that caramelizes in the oven. A frequent mistake is not spacing the cookies about 2 inches apart, which can cause them to bake into each other. Flattening them slightly helps achieve the right shape, because they will spread modestly, keeping a soft center with set edges.
Bake: Bake in the middle rack of the oven for 12 to 13 minutes, or until the edges of the cookies look set, but the centers are still soft and puffy. Remove the cookie sheet from the oven and let the cookies set for 5 to 10 minutes before using a spatula to transfer them to a cooling rack.: While the cookies bake for about 12 to 13 minutes, your kitchen will fill with a sweet, fruity aroma and the cookies will puff and settle. Look for edges that appear set and faintly golden while centers remain soft and puffy, that visual cue is key to avoiding overbake which dries them. When you remove the sheet, the cookies will continue to set on the hot tray, so letting them rest for 5 to 10 minutes before transferring prevents breakage and yields a tender center with slightly crisp edges. A common trap is pulling them out too late, which loses the gentle chew we aim for.
Serve & Store: Enjoy immediately, or store in an airtight container on the counter for up to 4 days. You can also store your cookies in the freezer for 1 to 2 months and de-frost as necessary.: After cooling on a rack, the cookies feel pleasantly mellow, with restrained sweetness and concentrated strawberry notes. Store in an airtight container on the counter up to four days to keep them soft, or freeze for longer storage, noting that freezing locks in texture but may slightly reduce surface sparkle. When thawing, let them come to room temperature in the container to prevent condensation that can soften the exterior. Avoid leaving them exposed to air, which will dry them out quickly.