Preheat the oven to 400°F.

Transfer butter to a small bowl and place in the freezer for a few minutes to get very cold.

Meanwhile, put flour, thyme, garlic powder, baking powder, pepper and salt into a food processor and pulse until mixed.

Remove butter from freezer and transfer to food processor.

Pulse until butter is the size of breadcrumbs.

Add walnuts and pulse once or twice.

While continuing to pulse, slowly add milk and pulse just until a wet dough is formed. (Avoid over processing so walnuts are not pulverized.)

Using a spoon, drop dough onto a parchment paper-lined baking sheet to form 8 scones.

Alternately, turn dough out onto a floured surface, pat into an 8-inch circle and cut into wedges.

Brush scones with remaining 1 tablespoon milk, then sprinkle bacon over the top, pressing to ensure it adheres.

Bake until golden and cooked through, 25 to 30 minutes.