Step 1
Combine 2 cups flour 1/2 cup sugar yeast and salt in a large bowl of a stand mixer fitted with the paddle attachment.
Step 2
Heat milk water and 4 tablespoons butter in a medium saucepan over low heat until warm to the touch. Pour into the flour mixture; beat on low speed until just combined. Increase speed to medium; add eggs and beat for 2 minutes scraping sides of the bowl occasionally. Gradually stir in up to 2 more cups flour mixing until a soft dough forms.
Step 3
Turn dough onto a lightly floured surface and knead until smooth and elastic about 10 minutes. Dough will be very sticky; use a scraper and add remaining flour only as needed. Shape dough into a ball and place in a large greased bowl; turn to coat. Cover with a towel and let rise in a warm draft-free place until doubled in volume about 1 hour.
Step 4
Punch down dough starting from the center then pushing in the edges. Transfer onto a lightly floured surface and cut dough in half. Cover with a bowl and let rest for 15 minutes.
Step 5
Meanwhile combine remaining 1/2 cup sugar lemon zest and mace in a small bowl. Melt 2 tablespoons butter in a small pan. Grease a 10-inch fluted tube pan with cooking spray.
Step 6
Cut each dough half into 16 pieces. Shape each piece into a ball by tucking ends under. Dip tops in melted butter and place half of balls in the tube pan; sprinkle with 1/2 of the lemon mixture. Repeat with remaining dough balls butter and lemon mixture. Cover with a towel; let rise in a warm place until doubled about 45 minutes.
Step 7
Preheat the oven to 350 degrees F (175 degrees C). Place tube pan on a cookie sheet.
Step 8
Bake in the preheated oven until bread is golden and sounds hollow when lightly tapped about 35 minutes. Cool in the pan for 5 minutes; remove and let cool on a wire rack.