Combine the 2 1/2 tablespoons flour (20 grams) and the 1/2 cup water in a small saucepan. Cook over medium heat, whisking constantly, until a thick paste forms. Add cream and honey and cook, whisking to blend, until honey dissolves. This should only take a few minutes.
Scrape mixture into a stand mixer bowl and add the milk powder, salt, 2 ½ cups of flour and Platinum yeast. Stir with the paddle attachment or by hand until things start to look pretty well blended, then beat in the egg.
Attach the dough hook and let the machine knead the mixture until smooth. When dough starts to look smooth, add pieces of butter (mixer still going) and continue kneading for another 5 minutes or until dough is smooth and elastic. It is a soft dough and just slightly sticky. You should be able to move it around with a scraper. Also, it should clear the sides of the bowl as it is kneaded . If it is sticking to the sides of the bowl, add 1 or 2 tablespoons of flour.
Rub a large bowl with butter or grease with oil or spray with cooking spray, then scrape the elastic dough into the bowl. Cover with plastic wrap and let rise in a warm place for about 45 minutes.
Meanwhile, grease and flour a 9x5 inch loaf pan. If you want, you can grease, then line with a strip of parchment, then grease and flour again.
Turn out dough onto a floured surface and punch it gently into kind of a rectangle about the size of the loaf pan. Cut into two halves and set them next to each other running down the length of the pan.
Cover loosely with a greased piece of plastic wrap and let shaped dough rise in a warm, draft-free place until doubled in size (dough should be just puffing over top of pan), about 45 minutes.
Preheat oven to 375° F. Beat remaining egg with 1 teaspoon water in a small bowl to blend. Brush top of dough with egg wash and sprinkle with sea salt or sesame seeds if desired.
Bake the bread until bread is deep golden brown and baked through, about 35 minutes.