Preheat oven to 250 F. Line a baking sheet with parchment paper and put in the oven to warm up.
Beat egg whites with a mixer (start slowly, add a few drops of lemon juice and cream of tartar, increase speed; when they hold soft peaks, gradually add sugar and beat until stiff peaks).
Take out the baking sheet and spoon meringue into 4 mounds, spread each into a flat round. Put in the oven and immediately decrease temperature to 225 F. Bake for at least 1.5 - 2 hrs. until crisp and pale beige in color. Cool and peel of the parchment.
Slice strawberries and stir with some Sherry, macerate 20 min and drain, reserving syrup. Beat heavy cream with a bit of sugar and add reserved syrup. Spoon cream over meringues and top with sliced strawberries. Eat immediately.