Make the cookie dough: In a large bowl, cream together the softened butter and granulated sugar until light and fluffy. Beat in the egg and vanilla extract. In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Chill the dough: Cover the dough and refrigerate for at least 2 hours, or preferably overnight. This chilling period is crucial for preventing spreading and making the dough easier to handle.
Preheat and prepare: Preheat oven to 375°F (190°C). Grease a muffin tin (12 cups is ideal, but you can use two batches if needed).
Shape the cookies: Scoop rounded tablespoons of dough and press them into the muffin cups, creating a cup shape. You can use your fingers or the back of a spoon to press the dough up the sides and create a well in the center.
Bake: Bake for 12-15 minutes, or until the edges are lightly golden brown. Be careful not to overbake. The cookies will be soft.
Cool: Let the cookies cool in the muffin tin for a few minutes before carefully transferring them to a wire rack to cool completely.
Prepare the filling: In a large bowl, beat the softened cream cheese until smooth. Add the powdered sugar and vanilla extract and beat until well combined. In a separate bowl, beat the heavy cream until stiff peaks form. Gently fold the whipped cream into the cream cheese mixture.
Prepare the strawberry topping: In a medium saucepan, combine the sliced strawberries, granulated sugar, and lemon juice. Cook over medium heat, stirring occasionally, until the strawberries soften and release their juices, about 5-7 minutes. The mixture will thicken slightly. Let cool slightly.
Assemble the cups: Once the cookie cups are completely cooled, fill each cup with the cream cheese filling. Top with the strawberry mixture.
Serve: Serve immediately or refrigerate for a short time before serving.