Preheat oven to 375 degrees F.
Begin by soaking the raisins. Pour hot water over raisins and add rum. Cover with plastic wrap and set aside while you prepare the rest of the dish - let rest for at least 45 minutes
Split pears down the middle retaining stem and skin. Using a melon-baller, remove the cores. Add brown sugar and butter to a large nonstick skillet over medium-high heat until just melted. Add lemon juice and pears, cut side down, to pan then baste with melted butter and sugar. Pop into the oven for 15 to 17 minutes until pears are tender. When done remove from oven and baste once more.
For the rum raisin mascarpone:
Whisk mascarpone cream gently to loosen it up. Strain raisins and gently fold into the cream. Serve pears on a plate topped with a scoop of mascarpone cream and drizzle with pear pan juices. Top with crumbled amaretto cookies.