Prepare Strawberry Jam: In a medium saucepan, combine 1 cup of finely diced fresh strawberries with 1/4 cup of granulated sugar. Cook over medium heat for about 45 minutes, mashing halfway through. The jam is ready when it thickens and reduces to about 1/3 cup.

Make Cream Cheese Filling: In a mixing bowl, combine 8 oz of softened cream cheese, 1/4 cup of granulated sugar, and 1/2 tsp of vanilla extract. Beat until smooth and creamy. Divide into 18 equal portions, flatten into discs, and freeze until solid.

Prepare Cookie Dough: In a large bowl, beat 1 cup of softened unsalted butter with 1 cup of granulated sugar until light and fluffy, about 3-5 minutes. Add 1 large egg and 1 tsp of vanilla, mixing until pale and creamy.

Combine Dry Ingredients: In a separate bowl, whisk together 3 cups of flour, 1/2 tsp of baking powder, and 1/4 tsp of salt. Gradually add to the butter mixture, stirring until just combined.

Assemble Cookies: Divide the cookie dough into four portions. Place a teaspoon of homemade thick strawberry jam in the center of one portion, then encase it with a cheesecake disc before shaping into a slightly flattened disc.

Bake: Preheat oven to 350°F (175°C) and line baking sheets with parchment paper. Bake the cookies for 11-12 minutes until edges are golden and centers remain soft. Cool on trays for 10 minutes before transferring.