Your favourite brownie mix, baked in a tray 1/2- 3/4 inch thick, cut into 3 1/2-inch circles
Toss together strawberries, lemon juice and 1/4 cup sugar in a bowl. Leave to macerate for 1-2 hours. Crush with fingers or a fork.
In a large mixing bowl with either a whisk or an electric mixer, whip eggs and remaining 3/4 cup sugar until pale and fluffy, about 1 minute. Whisk in milk, cream and vanilla until fully combined.
Pour base into ice cream maker and churn for 20 minutes. While still churning, pour in macerated strawberries and churn 5-10 minutes more. Pour into an airtight container and freeze for at least 4 hours before scooping.
Prepare the meringue. In a heatproof bowl fitted over a saucepan of simmering water, whisk sugar, egg whites and cream of tartar constantly until dissolved, about 2 minutes. Remove from heat and whisk with an electric mixer until stiff and glossy, about 10 minutes. Whisk in vanilla. Use immediately.
To assemble: Place a packed scoop of ice cream (about 3-4 ounces) on brownie base. Using a spoon or offset spatula, spread meringue all over ice cream and brownie. Use a swirling motion to create texture. Toast meringue with a torch and enjoy.