Preheat the oven to 425°. Don't line or grease a thin rimmed baking sheet.
Slice baguette into thin slices. (You will get about 30 slices, not counting the end pieces.)
Brush each slice of bread with olive oil on both sides. Place the bread slices onto the rimmed baking sheet in one layer. Sprinkle some coarse salt and black pepper over the bread and bake for 6-8 minutes, until golden brown.
Melt Brie On Some Crostini:
Slice the rind off the Brie cheese and discard it. Cut the Brie cheese into small pieces and divide them evenly among 20 crostini pieces.
Place the baking sheet with cheese topped crostini back into the oven for just a couple more minutes, until Brie is melted. Take out and set aside.
Prepare toppings:
Dice the pears and divide it in two even halves.
In a small cooking pan, cook diced onion until softens. Add half of the pears and cook until pears and onions are soft and start to golden. Mix in dried cranberries and cook everything together a few more minutes, until onions and pears are golden. Take off the heat and stir in thyme.
In a small bowl, combine remaining half of the diced pears and pomegranate seeds and mix.
Spread some mascarpone cheese on the remaining 10 slices of baguette and divide the pear/pomegranate topping evenly over each slice.
Divide the sautéed pear/cranberry topping evenly over the 10 Brie crostini.
Divide the prosciutto over remaining 10 Brie topped crostini and spread some pine nuts over the prosciutto.
Drizzle honey over the prosciutto and pomegranate crostini. (If you wish, you can drizzle honey over all of the crostini.)