Marshmallows:

Line an 8 x 8-inch square tin with parchment, allowing a 1-inch overhang on all sides. Spray with nonstick spray.

Pour 120 milliliters water into a large mixing bowl (if using a hand mixer), or the bowl of a stand mixer. Sprinkle the powdered gelatin evenly over the water.

In a large, heavy-bottomed stock pot, combine granulated sugar, corn syrup, remaining water, and fine sea salt. Bring to a boil and boil, without stirring, until syrup reaches 240° F / 116° C on a digital thermometer.

Carefully pour hot syrup over gelatin mixture. Mix on high speed for 2-3 minutes, until mixture begins to thicken.

Add 1-2 drops of purple gel food coloring and continue to mix on high speed until very thick and voluminous, about 8-9 minutes more.

Mix in the ground dried lavender and vanilla bean paste.

With an oiled flexible rubber spatula, scrape marshmallow into prepared tin.

Loosely cover with a well-oiled sheet of aluminum foil. Allow to set at room temperature until firm, at least 4 hours or overnight.

Cutting and Coating:

In a small bowl, whisk together confectioner’s sugar and ground dried lavender.

Cover a large chopping board with a sheet of parchment, and dust generously with cornflour mixture. Turn marshmallow slab out onto dusted surface. Sift top of slab with more of the powder.

With a well-oiled chef’s knife, cut the slab into 6×6 rows, for 36 square marshmallows, or 8×8 rows, for 64 marshmallows. If desired, you can also use an oiled metal cutter to cut the slab into hearts, stars, or other shapes.

Toss the marshmallows in remaining cornflour mixture, coating all sides evenly.

Store lavender marshmallows in an airtight container at room temperature for up to 1 month.