1. Make the brioche dough: whisk the yeast into the lukewarm milk. Place 1 1/4 cups flour in a large mixing bowl and stir in the milk mixture. Cover and let sit at room temperature for 30 minutes.
2. Combine the butter, sugar, and salt in a mixing bowl and beat with a wooden spoon until mixture is blended well. Add the eggs, 1 at a time, blending well. Then add the remaining flour, and blend well.
3. Add the yeast mixture and knead until smooth, about 15 minutes. (The dough should still be slightly sticky; if it's not, add a little more milk.)
4. Place dough in a lightly buttered bowl and cover with a damp towel. Allow the dough to rise in a warm place until it doubles, about 2 hours.
5. Punch the dough down and cover again. Keep refrigerated at least 2 hours.
6. Preheat oven to 375 degrees.
7. When ready to use, roll out dough on an oiled baking sheet into a rectangle 2 inches longer than the sausage on each end and twice as wide. Cut the dough down the middle into 2 long halves. Center the sausage on one piece of the dough. Place the other piece of dough on top and squeeze the edges to seal. Make a design with the extra dough if desired. Let sit for 15 minutes. Brush the top of the dough with cream, and bake at 375 degrees for 25 minutes, or until golden brown. Cut into crosswise slices, approximately 3/4 inch thick, and serve immediately.