Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.

In a bowl, combine ground beef, breadcrumbs, egg, onion, garlic, salt, and pepper. Mix gently until just combined. Overmixing makes meatballs tough.

Roll into 1.5-inch meatballs (about 24). Place on prepared sheet.

Bake 15 minutes until browned and cooked through (internal temp 160°F/71°C).

While meatballs bake, make glaze: In a small saucepan, whisk together iced coffee, ketchup, brown sugar, vinegar, Worcestershire, and paprika. Bring to a simmer over medium heat.

Cook glaze 5-7 minutes, stirring often, until thickened enough to coat a spoon. It should reduce by about a third.

Remove meatballs from oven. Pour glaze over them, turning to coat evenly.

Return to oven for 5 minutes, then broil on high for 2-3 minutes for a sticky, caramelized finish. Watch carefully to avoid burning.

Let rest 5 minutes before serving. The glaze will set slightly.