MSK instance size using CDK

According to the CDK documentation (https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-msk-cluster-brokernodegroupinfo.html#cfn-msk-cluster-brokernodegroupinfo-instancetype), which is validated by my testing, the smallest broker instance type supported by CloudFormation or the CDK is kafka.m5.large. My use case does not warrant that large in size, and indeed, one can be created via the console of type kafka.t3.small. How can I create an MSK cluster of type kafka.t3.small via CF/CDK?