Preheat the oven to 180°C (approximately 350°F). Line a baking sheet with parchment paper.
Mix the flour, sugar and baking powder in a bowl. Add the salt and chopped butter. Knead well. Pour in 300 ml (approximately 1.25 cups) of cream and knead until a smooth dough is formed.
Roll out the dough on a floured surface until about 1 cm thick. Cut out about 16 hearts. Brush the hearts with the melted butter. Bake for about 15 minutes, until golden brown.
Rinse the strawberries. Set aside 8 strawberries. Cut the remaining strawberries into slices.
Beat the remaining cream until stiff. Spread 2/3 of the cream over 8 of the hearts. Top with sliced strawberries and drizzle with strawberry jam. Gently press the remaining hearts on top of the cream and sprinkle with a little sugar. Decorate each tart with a dab of the remaining cream and a whole strawberry. Serve immediately.