Reduce water to a simmer and add in the ErySweet, cornstarch, and lemon juice. Stir until ErySweet and cornstarch are dissolved.
Add in the strawberries and continue to simmer for a half hour, stirring often. Set aside.
Cream ErySweet and butter together using a stand mixer until smooth, about 3 minutes.
Add in 1 egg, zest and vanilla. Scrape the sides of the mixing bowl with a spatula and continue mixing.
Sift the salt and flour together and add to the wet mixture. Beat until fully blended, then add the water and beat an additional 2-3 minutes.
Lay parchment or wax paper on counter, and place dough in the center. Top with a second piece of parchment/wax paper and use a rolling pin to flatten the dough until ⅛ inch thickness. Refrigerate 3-5 hours.
Preheat oven to 350ºF.
Once dough is fully chilled, remove from fridge and place on counter.
Remove the top layer of parchment/wax paper and cut into 2-3 inch wide circles.
Drop a few pieces (2-4 depending on size before cutting) of the strawberries in the center of a cookie.
Pick up the cookie and using your pointer fingers and thumbs, fold sides up to create a triangle. Pinch the seams where the sides meet, creating a little nest for the strawberries.
Place on Parchment lined cookie sheet.
Beat the remaining egg in a small bowl and use for an egg wash. Generously brush the egg wash on the cookies, and place in oven for 12 to 15 minutes until they are a light golden color.