Oatmeal Lace Cookies:

Preheat oven to 360° F / 180° C.  Line a tray with parchment, and set aside until ready to use.

In a medium saucepan, melt the butter over medium-low heat. Add the brown sugar and stir until the sugar melts.

Remove from heat. Stir in flour, cinnamon, and salt, followed by vanilla extract. Set aside and allow mixture to cool for a few minutes at room temperature.

With a wooden spoon or flexible rubber spatula, stir the egg into the sugar mixture. Add the oats and the chopped ginger and stir until fully combined.

Drop batter by the teaspoonful onto prepared tray, allowing 2-3 inches of space between each spoonful. (These cookies will spread!)

Using damp fingers or the back of a metal spoon dipped in water, smooth the batter into thin discs, about 2 1/2 inches in diameter.

Bake for 10-12 minutes, or until deeply golden brown.

Cool completely on tray. While cookies cool, prepare the ganache.

Chai-Spiced Chocolate Ganache:

In a small saucepan, warm the cream over low heat. Remove from heat, add the tea bags. Cover and set aside to infuse, at least 15 minutes.

With a fine mesh strainer, strain the infused cream to remove the tea bags and any loose bits of tea. Reweigh the cream, and, if necessary, add more cream to make up 160 milliliters (2/3 cup). Return to saucepan and rewarm over low heat.

Meanwhile, melt chocolate over a bain marie or double boiler.

Whisk warm, chai-infused cream into the melted chocolate, followed by the softened butter.

Set aside to cool at room temperature while you prepare for assembly.

Assembly:

Gently peel cooled lace cookies from the baking parchment.

On a clean sheet of parchment, pair each cookie with another of similar size (not unlike finding mates for your French macarons!) Flip one of each pair so that the bottom side of the cookie faces upward.

With a metal whisk, whisk your ganache until thick, creamy, and easy to pipe. (It might take a bit of whisking to reach the desired consistency, but don’t worry–it will firm up eventually!) The ganache should remain fluid enough to flow easily from a piping bag, and spread evenly when sandwiched between two cookies.

Scoop ganache into a disposable piping bag. Pipe a generous dollop into the middle of each cookie. Top with the second cookie and press down gently, allowing ganache to spread to the edges.

Store sandwich cookies in an airtight container at room temperature for up to three days. Oatmeal lace cookies also freeze well.