Prepare an ice bath and place a strainer over a medium bowl. Set nearby.
Make the crème anglaise: In a small saucepan, heat the milk, heavy cream, ¼ cup (50 g) of sugar, and the vanilla bean pod over medium heat for 2-3 minutes, until it begins to steam. Remove the pan from the heat.
In a medium bowl, combine the egg yolks, remaining ¼ cup (50 g) of sugar, and the salt and whisk together. Continue whisking and ladle in the milk mixture. Once combined, return the saucepan to medium heat, begin to whisk the milk mixture, and slowly pour in the egg mixture.
Cook the custard, continuously whisking to ensure the egg yolks don’t cook on the bottom, for about 5 minutes, until it coats the the back of a spoon.
Set the bowl with the strainer in the ice bath and strain the creme into the bowl. Whisk until cooled, about 5 minutes. Cover and refrigerate until ready to serve.
Add the strawberries, 2 tablespoons of sugar, and the lemon juice to a small saucepan. Cook over medium heat for about 5 minutes, stirring occasionally, until the strawberries are softened but still vibrant red. Remove the pan from the heat.
Strain the strawberry mixture through a fine-mesh sieve into a medium bowl. Use a spatula to press the berries through, making a strawberry puree. Discard the pulp and set the puree in the refrigerator to cool.
Set 6 ramekins on a baking sheet and coat the insides with the softened butter. Sprinkle 2 tablespoons of sugar among the ramekins and shake each to coat the bottom and sides with sugar.
Add the egg whites, cream of tartar, and salt to a large bowl. Using an electric hand mixer, beat the whites on medium-high speed until foamy. Add the remaining ⅓ cup (65 g) of sugar in small increments, continuing to beat until the whites are stiff and glossy.
Using a spatula, carefully fold in the strawberry puree.
Fill each ramekin with the strawberry-egg white mixture and level off the tops with a butter knife. Run a clean thumb around the inside edge of each ramekin to allow the soufflés to rise properly.
Bake the soufflés for 10-12 minutes, until the tops are light brown. Avoid opening the oven prematurely, so the soufflés don’t fall.
Serve the soufflés immediately with the crème anglaise poured over the top.