HEAT olive oil in skillet set over medium-high heat; SAUTÉ onion for about 5 minutes or until softened but not browned.
ADD mushrooms, garlic, thyme, rosemary, half each of the salt and pepper, and hot pepper flakes; COOK for 5 to 7 minutes or until cooked through.
STIR in balsamic vinegar and lemon zest; COOK for 1 minute.
TOAST flatbread on baking sheet in 400°F oven for about 5 minutes or until golden and heated through.
Meanwhile, in saucepan set over medium heat, POUR in enough water to come 3 inches up the side; ADD white vinegar and BRING to simmer over medium-high heat.
CRACK eggs into small dish; SLIDE, one at a time, into simmering water. COOK for 3 to 4 minutes or until desired doneness. REMOVE with slotted spoon; BLOT on paper towels.
TOP flatbreads with sautéed mushrooms and poached eggs. SPRINKLE with remaining salt and pepper. GARNISH with chives.
This recipe is an excellent source of choline and protein, and a good source of vitamin A, vitamin D and folate.