You will be baking 32 cookies in two batches, so each batch will have 8 cookies per sheet. Preheat oven to 350°F and line two baking sheets with parchment paper.

In a large mixing bowl, whisk together the rice milk, sugar, oil, vanilla, and orange zest until smooth.

Sift in half of the flour along with the cornstarch, baking powder, and salt. Mix well. Add the remaining flour and stir until you have a soft, pliable dough.

Dust your hands lightly with flour. Pinch off about a tablespoon of dough at a time. Roll it into a ball, then into a log about 1½ inches long. Flatten with the palm of your hand into a 2-inch by 1-inch oval, straightening the edges with your fingers. Don't try to be perfect about it. These are homemade.

Place 16 cookies on the baking sheets (8 per sheet) about an inch apart. They don't spread much. Cover the rest of the dough with a damp towel while the first batch bakes.

Bake for 10 to 12 minutes, until the bottoms are just golden and the tops still look barely set. Pull them sooner than feels right. They firm up as they cool. Let them rest on the sheets for 2 minutes, then transfer to a wire rack to cool completely.

Shape and bake the second batch the same way. You should end up with 32 cookie halves total, which sandwich into 16 finished cookies.

While the cookies cool, melt the chocolate. Place the chopped chocolate or chips in a heatproof bowl and microwave in 30-second bursts, stirring between each, until smooth. To melt over the stove instead, set the bowl over a small pot of barely simmering water (make sure the bowl doesn't touch the water) and stir until smooth. Let the melted chocolate sit for a few minutes until it's still pourable but no longer hot.

Spoon a small amount of melted chocolate onto the flat side of one cookie and sandwich with another cookie, flat sides together. Don't press hard or the chocolate will squeeze out the edges. Set the assembled sandwiches on a tray.

Refrigerate for at least an hour, until the chocolate is firm. Bring to room temperature before serving.