1. Preheat the oven to 180°C (350°F). Line a 23x23cm baking tin* (with loose bottom) with baking parchment and grease lightly. Set aside. Melt the butter and let it cool down a bit.

2. Add the melted butter, both sugars, and the vanilla extract to a large bowl and mix until light and fluffy. Add the eggs separately and mix well after each addition. Combine flour, baking soda, and salt and add it to the large bowl – mix until just combined.

3. Add about half of the batter to the prepared baking tin and spread evenly. Distribute the raspberry jam evenly on top – keep about 1cm along the edges free of jam. Spoon the remaining batter on top of the jam, starting around the edges and working towards the center to cover the jam evenly with the batter. You don’t want the batter and jam to mix. Working with an offset spatula* works best here – distributing the batter evenly as well as the jam.

4. Bake the blondies in the preheated oven for about 45-50 minutes, or until a wooden skewer inserted into the blondies comes out clean. If they get a bit too dark, cover them with some aluminum foil or baking parchment and continue baking until done. Take the blondies out of the oven and let them cool down inside the baking tin for about 20 minutes, then remove and let cool down completely on a wire rack.

5. For the glaze, mix confectioners’ sugar with vanilla extract and some heavy cream to get a thick glaze that is not too runny – adjust with heavy cream or more confectioners’ sugar to get the right consistency. Pour the glaze over the cooled blondies and spread evenly. Sprinkle with rainbow sprinkles to your liking and let the glaze set completely before cutting the blondies into squares. Since the blondies are quite sweet, we cut them normally into 16 or even 20 pieces.