Here are a couple recipes that seem pretty simple. If you try them, let me know.
Celeriac Au Gratin (from the A to Z cookbook put out by the Madison, WI CSA coalition)
2 large celeriac, peeled
1 T flour
salt & pepper to taste
2 T butter
1 C veggie stock
1 C grated cheese, swiss or cheddar
Clice the peeled celeriac into 1/8 " pieces. Simmer in water over medium heat until just tender, 15-20 minutes. Drain. In medium saucepan, melt butter, add flour and cook until golden. Remove from heat and slowly whisk in stock. Return to heat and stir until boiling. Cook until thick. Season with salt and pepper. Heat oven to 375 degrees. Place drained celeriac in a shallow 8" baking dish; pour sauce over celeria. Sprinkle cheese on top and bake until golden brown, about 15 minutes. Makes 4 to 6 servings.
Kabocha squash Japanese style
1 squash, cut into 2" cubes
1/2 C soy sauce
1/4 C honey or brown sugar
Bring several inches of water to a boil in a saucepan. Cube and add squash, leaving the skin on (it's easier to remove after it's cooked when you are eating it.) Add more water to cover if needed. Bring to a boil again, reduce heat to medium-low and add soy sauce and honey. Cook 10 to 15 minutes or until squash is pierced easily by a fork. Drain and serve. Makes 4 to 6 servings.