In a medium saucepan, combine finely diced fresh strawberries with 1/4 cup of granulated sugar. Cook over medium heat for about 45 minutes, mashing the strawberries halfway through until the mixture thickens to approximately 1/3 cup.

In a mixing bowl, beat the softened cream cheese with 1/4 cup of sugar and 1/2 tsp of vanilla extract until smooth. Divide into 18 equal portions, flatten into discs, and freeze for 30 minutes.

Cream together 1 cup of softened unsalted butter and 1 cup of sugar until fluffy. Add 1 large egg and mix until smooth. In another bowl, whisk together 3 cups of flour, 1/2 tsp of baking powder, and 1/4 tsp of salt, then incorporate into the wet mixture.

Divide the cookie dough into four portions. Flatten a piece, place a frozen cheesecake disc on top, and add a spoonful of the strawberry jam. Encase the filling with the dough.

Preheat the oven to 350°F (175°C). Shape dough portions into balls, place on parchment paper, and bake for 11-12 minutes. Let cool for 10 minutes before transferring to wire racks.