Melt butter in a frying pan over medium heat. Add shallot; cook and stir for 1 minute to soften. Add thinly sliced pears; cook until soft, about 5 minutes. Pour in white wine, brown sugar, thyme, salt and pepper; increase heat to medium-high and simmer until the liquid has evaporated and the pears have lightly caramelised, about 10 minutes. Set aside.
Cut a Brie-sized hole in the top of the crusty bread to within 1cm of the bottom. Cut the removed bread into pieces for serving; set aside. Score the Brie around it's edge, using a paring knife to cut .5cm deep. Cut in half by looping a strand of very thin string or dental floss around the scored Brie and pulling the ends in opposite directions.
Place the bottom half of the Brie, cut-side-up, into the loaf. Top with 1/2 of the pear mixture and sprinkle with 1/2 of the almonds. Place the remaining brie half on top, cut-side-down, spread with remaining pear mixture, and sprinkle with remaining almonds. Place on a baking tray.
Bake in preheated oven for 45 minutes or until soft and gooey. Serve with sliced bread and crackers.