Oatmeal Lace Cookies:

Preheat oven to 360° F (180° C).  Line 2 half sheet rimmed baking trays* with silicone mats.

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 all purpose flour, ground cinnamon, and kosher salt, followed by vanilla extract. Set aside and allow to cool 5 minutes at room temperature.

With a wooden spoon or flexible rubber spatula, stir in the egg, followed by the old-fashioned oats and the chopped candied ginger.

Drop batter by the teaspoonful onto prepared trays, allowing 3 inches of space between each spoonful.*

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

Bake in preheated oven for 11-12 minutes, or until deeply golden brown.

Cool completely on tray. Repeat with remaining batter.

Chai-Spiced Chocolate Ganache:

In a small saucepan, warm the cream over low heat. Remove from heat, add the chai tea bags. Cover and set aside to infuse, at least 30 minutes, or up to 1 hour.**

With a fine mesh strainer, strain the infused cream to remove the tea bags and any loose bits of tea. Reweigh the cream, or re-measure in a measuring cup. 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 the warm, chai-infused cream into the melted chocolate, followed by the softened butter.

Set aside to cool at room temperature until ready to assemble.

Assembly:

Pair each oatmeal lace cookie with another of similar size (not unlike finding mates for your French macarons!) Flip half of each pair so that the bottom side of the cookie faces upward.

With a metal whisk, whisk ganache until thick, creamy, and easy to pipe.***  The ganache should remain fluid enough to flow easily from a piping bag, and spread evenly when sandwiched between 2 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 3 days or layer between sheets of parchment and freeze for up to 3 months.