Dissolve yeast in warm milk and stir in 1/4 cup flour.

Whisk eggs in a large bowl.

Add yeast mixture and remaining 1 1/4 cups all-purpose flour; stir until smooth.

Add sugar, salt, and butter; mix well.

Add pastry flour 1/2 cup at a time, mixing well.

Knead dough on a floured surface for 10 minutes until smooth and firm, adding all-purpose flour as needed.

Transfer dough to a clean bowl, cover, and let rise for 2 hours or until doubled.

Wash and chop greens and spinach into 1-inch lengths.

Heat bacon grease, butter, or oil in a skillet over medium heat.

Add garlic and scallions; cook for 1 minute until scallions soften.

Raise heat, add greens and salt, and cook, stirring until wilted.

Cover, lower heat, and steam for 1 minute.

Cool greens to room temperature and taste for salt.

Place sweet potatoes in a pot with 1 inch of water, bring to a boil, cover, and simmer until tender.

Drain sweet potatoes.

Wash and chop greens into 1-inch lengths.

Heat grease, butter, or oil in a skillet over medium heat.

Add garlic and sauté briefly, then toss in greens and salt; raise heat and cook, stirring until wilted.

Cover, lower heat, and steam for 1 minute.

Cool to room temperature, then toss with sweet potatoes and black pepper; taste for salt.

Preheat oven to 450F and grease a baking sheet.

Divide dough in half.

Cut each half into unequal pieces for the bottom and top crust.

Flatten the larger piece and roll it into a 16x10 inch oval.

Roll the smaller piece into a 15x8 inch oval.

Place the larger dough piece on the baking sheet.

Mound filling on the dough, leaving a 1-inch rim.

Place the top crust over the filling and stretch the sides to fit.

Fold the bottom dough edges over the top and twist to seal.

Cut about 10 slits in the top crust.

Brush with melted butter.

Bake at 450F for 8 minutes, then lower heat to 400F and bake for 8-10 minutes until golden brown.

Cool on a wire rack for 20 minutes before serving.