-
Preheat oven to 425 F. Toss celery, onions, carrots and fennel in oil to coat. Spread in single layer over 15x10x1 baking pan. Roast stirring occasionally, until lightly browned, 20 to 25 minutes. Cool.
-
Reduce oven to 350 F.
-
In a large saucepan melt the butter. Stir in flour until smooth. Gradually whisk in the broth, and then add the thyme. Bring to a boil, stirring constantly; reduce heat and simmer 10 minutes. Add the roasted vegetables, ham, tarragon, salt and pepper, cooking until heated through. Transfer to a greased 9x13 baking pan.
-
For the biscuits, pulse flour, baking powder, salt and baking soda in a food processor until blended. Add the cubed butter, pulse until butter is the size of peas. Transfer to a large bowl, stir in buttermilk until no flour is visible. Turn onto floured surface; knead gently 8 to 10 times. Roll dough into 13x9 rectangle; cut into shapes of your choice.
-
Arrange biscuit pieces, overlapping slightly, over ham mixture. Bake until biscuit topping is golden brown, 25 to 30 minutes. Let stand 10 minutes before serving.