For the small batch blondies melt together the butter and 100gr light brown sugar, add a pinch of salt and the baking powder, stir in 1 large egg yolk, the sifted flour and finally 20gr chopped white chocolate, transfer the mix into a 10x10cm parchment-lined pan and bake in a 175C oven for 20min.
Dissolve the cornstarch in 50ml whole milk, leave to rest.
In a small saucepan over medium heat combine the heavy cream, the leftover milk, malted milk powder, sugar and a pinch of salt, stir, bring to an almost boil, add 100gr chopped white chocolate, stir until fully dissolved. Add the cornstarch milk and cook constantly stirring until thickened. Take off heat, add the cream cheese, stir until smooth and combined. Cool to room temperature, then transfer into the fridge overnight.
Freeze in your ice cream maker according to the manufacturer's instructions adding chopped blondie chunks (2/3 of the prepared amount) at the last couple minutes of churning. Store in an airtight container and keep in the freezer or spoon right away.