In a small saucepan, cook the sugar and butter over low heat, stirring, until the mixture turns light brown, about 3 minutes. Slowly add the milk and cook, stirring, until the mixture is smooth. Remove the pan from the heat and stir in the sliced almonds. Spread the topping over the tart base and bake for 10 minutes, or until sizzling and set. Let cool slightly. Cut the tart into wedges and serve warm or at room temperature.