Place the hulled strawberries and whole strawberries in a bowl and crush lightly with a fork or potato masher. Mix in the grenadine and set aside.
Place peppercorns in a pan. Heat on a stove for a few minutes, until the corns crack and roast. Allow to cool and then coarsely crush using a mortar and pestle.
In another bowl mix the caster sugar with the balsamic, vanilla and the liqueur or vodka. Mix in the single cream.
Beat the mascarpone and mix into the single cream mixture.
Spoon a little of the crushed strawberries into the bottom of Martini glasses, wineglasses or Knickerbocker Glory glasses. Spoon over a little of the cream mix and sprinkle with some of the peppercorns.
Repeat until the glasses are full, finishing with the cream and the final sprinkle of pepper. Garnish with whole or cut strawberries.