Sift the matcha powder into a small bowl to remove clumps. Add the chilled brewed green tea (0.25 cups) and the 2 tsp granulated sugar. Whisk vigorously with a small whisk or a fork until a smooth, lump-free slurry forms.

Combine liquids

In a blender, pour 1.5 cups almond milk and 0.25 tsp vanilla extract. Add the matcha slurry from the previous step. Taste and adjust sweetness: if you prefer sweeter, add up to 1 tsp more sugar or 1 tbsp simple syrup.

Blend with ice

Add 2 cups of ice cubes to the blender. Pulse once to break the ice, then blend on high until the mixture is thick, smooth, and slushy (about 30–45 seconds depending on blender). If the mixture is too thin, add a few more ice cubes and blend again; if too thick, add up to 2 tbsp more milk.

Assembly & Toppings

Prepare glass and mochi

If the mochi are refrigerated and firm, let them sit at room temperature for 5–10 minutes so they soften slightly (they should be pliable). Place 2 of the mochi pieces into the serving glass or cup along the sides or bottom so they're visible through the glass.

Pour frappe

Pour the blended matcha frappe into the prepared glass, leaving about 1.5–2 inches of headspace for ice cream and toppings.

Add ice cream and finish

Top the frappe with 1 generous scoop of matcha ice cream (reserve the second scoop if making two servings). Add the remaining mochi pieces on top or to the side of the scoop. If using, add 2 tbsp whipped cream, drizzle 1 tsp sweetened condensed milk over the top for extra richness, and dust with 0.25 tsp matcha powder.

Serve

Serve immediately with a wide straw and a spoon to scoop mochi and ice cream. Stir lightly if you want the ice cream to melt into the frappe for a creamier texture.