• Pre-heat your oven to 180℃/370℉, Line an 8″ Square Pan with greaseproof paper.
• In a small bowl, break up the white chocolate and melt in the microwave in 20 second intervals, stirring in between to make sure it doesn’t burn. Alternatively do this using a double boiler: Place the chocolate in a heat proof bowl resting on a small saucepan with simmering water. Stir until melted.
• In a large mixing bowl, whisk together the melted butter and both sugars. Add in the eggs and almond extract and mix again.
• Whisk in the melted white chocolate until fully incorporated. Add the flour and almond flour and fold to combine. Pour into the lined dish. 
• Bake 25-30 minutes until the topping looks just golden and the blondie looks firm (isn't wobbly). Let cool.

For the Frosting

• Add the butter and almond extract to a large mixing bowl. Beat with a whisk on high for a minute to soften/combine everything.
• Add half the powdered sugar, whisk on high. Then add the remaining half and whisk everything on high until fluffy. Add powdered sugar/milk as required to meet your desired consistency. Spread over the cooled blondies, and optional: scatter over slivered almonds and powdered sugar for that almond croissant look!