Preheat the oven to 350 degrees F (175 degrees C). Grease an 8-inch square baking pan and line the bottom and sides with parchment paper, leaving a 1-inch overhang. Lightly grease parchment.
Make the brownies: Melt butter in a small saucepan over medium-low heat; once melted, stir in the chocolate chips. Stir until the chocolate is completely melted and mixture is smooth; set aside and allow the mixture to cool to room temperature.
Whisk flour, cocoa powder, salt, and baking powder together in a medium mixing bowl; set aside.
Combine sugar and eggs in a large mixing bowl; beat with an electric mixer at medium speed until pale and fluffy. Mix in vanilla. Mix in the cooled, melted chocolate, adding it to the bowl in a slow, steady stream. Mix in the dry ingredients in increments, at low speed, until just combined. Finish incorporating the batter by hand with a rubber spatula if necessary. Scrape the batter into prepared pan.
Bake in the preheated oven until brownies begin to pull away from the sides of pan and a toothpick inserted into the center of the brownies tests clean, 30 to 35 minutes. Place the pan on a wire rack and allow brownies to cool completely, 30 to 40 minutes.
To prepare the topping, spread the raspberry jam evenly over the brownies in the pan, spreading right to the edge. Arrange the whole raspberries in a single layer over the jam.
Place the chocolate chips in a medium, heat-proof mixing bowl. Warm heavy cream and butter in a small saucepan over medium heat, stirring occasionally. When the butter melts and the cream begins steaming and bubbling at the edges, pour the hot cream mixture over the chocolate. Let stand for 3 to 5 minutes to allow chocolate to melt; add salt and whisk until completely smooth. Pour the chocolate ganache over the raspberries. Refrigerate until chocolate is set, about 30 minutes.
Carefully pull the brownies from the pan using parchment paper overhang; place on a cutting board and carefully peel the parchment paper from the sides. Slice into 9 squares and serve.