Combine warm water, brown sugar, and yeast in a large bowl and let stand for 5 minutes to activate the yeast.

Measure flour by lightly spooning it into dry measuring cups and leveling with a knife.

Add 1 cup of flour and melted butter to the yeast mixture and stir until just combined.

Cover the bowl and let the dough rise in a warm place for 30 minutes.

Add canned pumpkin, salt, and ground nutmeg to the flour mixture and stir until well combined.

Add 2 1/4 cups of flour and half of the grated Gruyere cheese to the dough and stir until a soft dough forms.

Turn the dough out onto a floured surface and knead until smooth and elastic, about 8 minutes, adding remaining 1/4 cup flour as needed to prevent sticking.

Place the dough in a large bowl coated with cooking spray, turning to coat the top, cover, and let rise in a warm place for 1 hour or until doubled in size.

Punch the dough down, cover, and let it rest for 5 minutes.

Divide the dough in half and shape each half into an 8-inch circle.

Place the dough circles on a baking sheet sprinkled with cornmeal.

Sprinkle the remaining Gruyere cheese and coarsely chopped walnuts evenly over the dough circles and press lightly to adhere.

Lightly coat the dough circles with cooking spray, cover, and let rise for 20 minutes.

Preheat the oven to 400°F.

Uncover the dough and bake at 400°F for 30 minutes, or until the loaves are browned on the bottom and the cheese melts, shielding with foil if necessary to prevent overbrowning.

Cool on a wire rack before slicing and serving.