Preparation Bring milk to simmer in small saucepan. Add butter and sugar; stir until butter melts. Pour mixture into large bowl. Add 1 cup room-temperature water and cool mixture until lukewarm (85°F to 95°F), about 10 minutes. Add yeast; stir to blend. Stir in olives, thyme and salt. Add 1 cup flour. Using wood spoon, stir until flour is incorporated. Add 3 cups flour, 1 cup at a time, and stir vigorously with wood spoon until incorporated after each addition. If necessary, add up to 1/2 cup more flour until dough is smooth and begins to pull away from sides of bowl. Oil large bowl. Transfer dough to bowl; turn to coat with oil. Cover bowl tightly with plastic wrap. For do-ahead version: Chill dough overnight. For same-day version: Let dough rise in warm draft-free area until doubled in volume, about 45 minutes (do not punch down dough). Position rack in center of oven and preheat to 500°F. Oil large baking sheet. Turn dough out onto floured work surface (to avoid deflating, do not punch down dough and do not knead dough). Divide dough into 2 equal pieces. Gently form (do not knead) each piece into baguette 15 inches long by 2 1/4 to 2 1/2 inches wide (dough will not be smooth). Transfer baguettes to prepared baking sheet, spacing evenly apart. Cover loosely with plastic wrap. Let rise in warm draft-free area until slightly puffed, about 30 minutes for refrigerated dough and 15 minutes for room-temperature dough. Brush top of each loaf lightly with egg white. Generously spray inside of oven with water (about 8 sprays); immediately place loaves in oven. Bake 10 minutes. Reduce oven temperature to 400°F and continue to bake until loaves are deep golden and sound hollow when tapped, about 35 minutes. Cool on rack.
Preparation Bring milk to simmer in small saucepan. Add butter and sugar; stir until butter melts. Pour mixture into large bowl. Add 1 cup room-temperature water and cool mixture until lukewarm (85°F to 95°F), about 10 minutes. Add yeast; stir to blend. Stir in olives, thyme and salt. Add 1 cup flour. Using wood spoon, stir until flour is incorporated. Add 3 cups flour, 1 cup at a time, and stir vigorously with wood spoon until incorporated after each addition. If necessary, add up to 1/2 cup more flour until dough is smooth and begins to pull away from sides of bowl. Oil large bowl. Transfer dough to bowl; turn to coat with oil. Cover bowl tightly with plastic wrap. For do-ahead version: Chill dough overnight. For same-day version: Let dough rise in warm draft-free area until doubled in volume, about 45 minutes (do not punch down dough). Position rack in center of oven and preheat to 500°F. Oil large baking sheet. Turn dough out onto floured work surface (to avoid deflating, do not punch down dough and do not knead dough). Divide dough into 2 equal pieces. Gently form (do not knead) each piece into baguette 15 inches long by 2 1/4 to 2 1/2 inches wide (dough will not be smooth). Transfer baguettes to prepared baking sheet, spacing evenly apart. Cover loosely with plastic wrap. Let rise in warm draft-free area until slightly puffed, about 30 minutes for refrigerated dough and 15 minutes for room-temperature dough. Brush top of each loaf lightly with egg white. Generously spray inside of oven with water (about 8 sprays); immediately place loaves in oven. Bake 10 minutes. Reduce oven temperature to 400°F and continue to bake until loaves are deep golden and sound hollow when tapped, about 35 minutes. Cool on rack.