Preheat oven to 400 degrees
To make the syrup: Mix water, sugar and almond extract in a pot, bring up to a simmer until sugar dissolves and turn stove off to let it cool.
To make almond paste: Mix almond flour, sugar, salt and lemon zest. Slowly add butter and blend on low with a hand mixer until a crumbly paste is created. Add egg and slowly mix until a paste is created.
To assemble your croissants: Dip the top of croissant in syrup (don't drench it just lightly dip) spread the almond paste on top and then stuff with Nutella and strawberries. Bake for 10-15 minutes or until golden. Dust with powdered sugar and enjoy!