Add the diced onions to a large skillet over medium-low heat along with 1 tbsp of butter. Cook, stirring occasionally, until softened and deeply golden, about 25-30 mins.

Once the onions are caramelized, stir in the balsamic vinegar and fresh thyme.

Cook for another 1–2 minutes, stirring until the vinegar is absorbed and the onions are glossy and fragrant.

Remove from heat and it let cool. Store in the fridge until ready to use.

In a large bowl, whisk together the flour, salt, sugar, and baking powder.

Add the grated cold butter and gently toss to coat. Add the chives, caramelized onions and cheddar.

Pour in the cold buttermilk and gently mix until a shaggy dough forms. Do not overmix.

Turn the dough onto a lightly floured surface and gently pat it into a rectangle. Cut the dough in half and stack the pieces on top of each other. and gently pat it out again. Repeat 2–3 times, keeping the dough cold and handling it as little as possible.

Roll the dough to about ¾–1 inch thick and cut into biscuits using a sharp biscuit cutter or knife. I like to use a bench scraper.

Freeze the biscuits until solid. 4 hours, but preferably overnight.

When ready to bake, Preheat oven to 425°F. Line a baking sheet with parchment. Place the biscuits on the prepared baking sheet. Bake for 15–20 minutes, or until tall and golden brown.

Let cool slightly before serving.