5 medium carrots, peeled and cut on the bias into 2-inch lengths

4 medium-large parsnips, peeled, halved lengthwise and cut on the bias into 2-inch lengths 

3 medium golden beets, peeled and halved, or quartered if large 

1 bunch radishes, trimmed and halved, or left whole if small 

4 sprigs thyme

2 garlic cloves, coarsely chopped 

3 tablespoons olive oil 

1/2 teaspoon freshly grated nutmeg 

Kosher salt and freshly ground black pepper 

1 teaspoon finely grated lemon zest