For the Dough:

1. Combine the yeast, warm water and 1 teaspoon sugar in a glass measuring cup or bowl, and let stand 5 minutes. If the yeast is alive and active, the mixture will bubble and foam. If it doesn’t, the yeast is likely dead. Toss it and start over.
2. While the yeast is proofing, beat 1/2 cup butter at medium speed with an electric stand mixer fitted with beater or paddle attachment until creamy. Gradually add 1/2 cup granulated sugar and 1 teaspoon salt and beat for 3 minutes or until light and fluffy. Beat in eggs, milk, and lemon juice. When yeast is ready, stir it into the mixture.
3. In a separate bowl, combine the flour and nutmeg. Gradually add the flour mixture to the butter mixture and beat at low speed for 2 minutes or until well blended.
4. Using the dough hook, knead the dough on speed 2 until smooth and elastic (about 5 minutes).
5. Coat a large bowl with cooking spray. Shape the dough into a ball and place it into the bowl, turning to grease top. Cover with plastic wrap and let rise in a warm place (80° to 85°) for 1 1/2 to 2 hours or until doubled in bulk.
6. When ready, punch the dough down and turn it out onto a lightly floured surface. Divide dough in half, setting one half aside while you work with the other.
7. Roll the first dough portion into a 20- x 12-inch rectangle. Carefully spread it with 1/4 cup softened butter, 1/2 cup fruit mixture, and 1/4 cup fresh fruit, if using. Then cut into 5 (12- x 4-inch) strips (I use a pizza cutter to do this).  Stack the 5 strips on top of each other and then cut the stack into 6 (4- x 2-inch) rectangles. This process is messy — don’t worry about getting it perfect.
8. Lightly grease 2 (9- x 5-inch) loaf pans with cooking spray. Then place the stacked rectangles, cut sides up, into the first prepared pan. Don’t worry if it doesn’t look like you have enough stacks to make a loaf — the dough will rise! Just spread them out as evenly as possible (not all bunched at one end of the pan).
9. Repeat procedure with the remaining dough to make the second loaf.
10. Next, whisk together powdered sugar, melted butter, honey, and egg white until blended. Spoon the mixture over loaves. Cover them loosely with plastic wrap and let rise in a warm place (80° to 85°) for an hour or until doubled in size.
11. Preheat oven to 350 degrees. Remove the plastic wrap and bake the loaves for 30 to 35 minutes or until golden brown. If the bread looks like it’s are getting too dark, you can shield them with an aluminum foil tent after 25 minutes.
12. Cool in pans on a wire rack for at 15 minutes. Remove from pans to a wire rack and drizzle with the citrus glaze and continue to let cool for at least 5 more minutes. Serve at room temperature.

For the Filling:

1. Combine sliced strawberries and rhubarb, sugar, lemon juice, and cornstarch in a medium saucepan.
2. Cook over medium heat, constantly stirring until the fruit breaks down, and the mixture turns into a jam-like consistency, about 10 minutes. You may have to crush some pieces of fruit with your spoon.
3. Set filling aside to cool while the dough finishes its rise.

For the Citrus Glaze:

1. Beat the powdered sugar and softened butter at medium speed with an electric mixer until blended.
2. Add orange zest, 2 tablespoons fresh orange juice, and lemon juice and beat until smooth.
3. If the glaze is too thick, add more orange juice.