For brownies:
4 ounces unsweetened chocolate, chopped
1/2 cup (1 stick) unsalted butter
1 1/4 cups (packed) golden brown sugar
1 tablespoon ground cinnamon
1/4 teaspoon salt
3 large eggs
1 teaspoon vanilla extract
3/4 cup all purpose flour
1 cup milk chocolate chips (about 6 ounces)

For brown sugar topping:
1 cup (packed) golden brown sugar
1/4 cup whipping cream
1 tablespoon unsalted butter
3/4 tablespoon vanilla extract
1/2 cup sliced almonds

Preheat oven to 325F.

Line 8-inch square baking pan with foil, extending foil over sides.

Stir unsweetened chocolate and butter in heavy large saucepan over low heat until melted and smooth.

Cool 5 minutes.

Whisk in sugar, cinnamon, and salt.
Whisk in eggs, 1 at a time, then vanilla.
Continue to whisk until batter is smooth, about 2 minutes.

Add flour and whisk just until blended.
Stir in chocolate chips.
Pour batter into prepared pan, smoothing surface.

Bake until tester inserted into center comes out with a few moist crumbs attached, about 35 minutes.
Cool completely in pan on rack.

Whisk sugar, cream and butter in heavy small saucepan over low heat until mixture is smooth and comes to boil. Remove from heat; mix in vanilla. Cool 10 minutes. Whisk until thick enough to spread.

Spread over brownie. Sprinkle with almonds. Let stand until topping sets, about 1 hour. Using foil as aid, lift brownie from pan.

Cut brownie into 16 squares.