In a metal shaker, add the strawberries and mash until the strawberries are smooth.
Add a little water to the strawberries and add several ice cubes. Give the mixture a few good shakes.
Strain into a cocktail glass, adding as much or little pulp as you like.
Add the vodka, lime juice, simple syrup and rhubarb bitters to the glass.
Add 5-6 new ice cubes to the shaker and pour in the mixture. Give it several good shakes. Strain out the ice or serve it on the rocks with fresh ice cubes.