Prepare your hot water using a kettle, the microwave, or the stove. You want the water to be hot but not boiling, about 175 degrees Fahrenheit.
Place your matcha sifter over the top of your matcha bowl. Using a matcha scoop, scoop the matcha powder into the sifter over the bowl. Use the back of the scoop to gently push the matcha powder through the sifter.
Pour the warm water over the top of the sifted matcha. Use a bamboo whisk to whisk the matcha and warm water together. You want to make back-and-forth motions with your bamboo whisk (an M or W motion). Whisk the matcha and hot water until no clumps remain, and the matcha is nice and frothy (about 1-2 minutes).
ALTERNATIVELY, IF YOU DO NOT HAVE A WHISK: Combine the matcha powder and hot water in a heat-proof cup and mix together with a handheld milk frother until the powder is dissolved and the mixture is frothy.
To a cocktail shaker, add the pistachio sauce, prepared matcha, the milk, and ice. Add the lid, and shake vigorously until chilled and frothy, then pour the iced matcha latte into a drinking glass.
In a separate cup, combine the chocolate malt powder, milk, and heavy cream. Use a handheld milk frother to froth until thick, creamy, and pourable.
Gently pour the chocolate cream cold foam over the iced matcha latte. Finish with a light sprinkle of McCormick Brown Butter Seasoning on top, and enjoy!