In a bowl mix the flour and ash together with a whisk until evenly distributed. Set aside.
Place water in a pot making sure it does not exceed halfway. Add the flour mixture while the water is cold as to not create large lumps. Whisk together until smooth.
Cook mixture on medium high, stirring constantly so the bottom of the pot doesn’t burn. Cook until thickened of desired consistency. *Add water to thin out. * To thicken, add a slurry of half water and flour (2 Tbsp cold water + 1 Tbsp flour).
-If desired, sweeten with sugar and enjoy it while it is warm.